diff --git a/.github/workflows/check_sast.yml b/.github/workflows/check_sast.yml
index 6fed88a6e6d8cc..b02f6fb76ad047 100644
--- a/.github/workflows/check_sast.yml
+++ b/.github/workflows/check_sast.yml
@@ -95,17 +95,17 @@ jobs:
         run: sudo rm /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@c793b717bc78562f491db7b0e93a3a178b099162 # v4.32.5
+        uses: github/codeql-action/init@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
         with:
           languages: ${{ matrix.language }}
           trap-caching: false
           debug: true
 
       - name: Autobuild
-        uses: github/codeql-action/autobuild@c793b717bc78562f491db7b0e93a3a178b099162 # v4.32.5
+        uses: github/codeql-action/autobuild@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@c793b717bc78562f491db7b0e93a3a178b099162 # v4.32.5
+        uses: github/codeql-action/analyze@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
         with:
           category: '/language:${{ matrix.language }}'
           upload: False
@@ -135,7 +135,7 @@ jobs:
         continue-on-error: true
 
       - name: Upload SARIF
-        uses: github/codeql-action/upload-sarif@c793b717bc78562f491db7b0e93a3a178b099162 # v4.32.5
+        uses: github/codeql-action/upload-sarif@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
         with:
           sarif_file: sarif-results/${{ matrix.language }}.sarif
         continue-on-error: true
diff --git a/.github/workflows/scorecards.yml b/.github/workflows/scorecards.yml
index 907519cb4d6621..8c061b16dcfb0b 100644
--- a/.github/workflows/scorecards.yml
+++ b/.github/workflows/scorecards.yml
@@ -73,6 +73,6 @@ jobs:
       # Upload the results to GitHub's code scanning dashboard (optional).
       # Commenting out will disable upload of results to your repo's Code Scanning dashboard
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@c793b717bc78562f491db7b0e93a3a178b099162 # v4.32.5
+        uses: github/codeql-action/upload-sarif@0d579ffd059c29b07949a3cce3983f0780820c98 # v4.32.6
         with:
           sarif_file: results.sarif
diff --git a/bignum.c b/bignum.c
index c39f74576a2c31..f5c58ab74312a4 100644
--- a/bignum.c
+++ b/bignum.c
@@ -2964,7 +2964,7 @@ int
 rb_cmpint(VALUE val, VALUE a, VALUE b)
 {
     if (NIL_P(val)) {
-        rb_cmperr(a, b);
+        rb_cmperr_reason(a, b, "comparator returned nil");
     }
     if (FIXNUM_P(val)) {
         long l = FIX2LONG(val);
diff --git a/compar.c b/compar.c
index 142cb12a0cfe77..1ab2520f1e6638 100644
--- a/compar.c
+++ b/compar.c
@@ -24,8 +24,8 @@ rb_cmp(VALUE x, VALUE y)
     return rb_funcallv(x, idCmp, 1, &y);
 }
 
-void
-rb_cmperr(VALUE x, VALUE y)
+static VALUE
+cmperr_subject(VALUE y)
 {
     VALUE classname;
 
@@ -35,10 +35,25 @@ rb_cmperr(VALUE x, VALUE y)
     else {
         classname = rb_obj_class(y);
     }
+    return classname;
+}
+
+void
+rb_cmperr(VALUE x, VALUE y)
+{
+    VALUE classname = cmperr_subject(y);
     rb_raise(rb_eArgError, "comparison of %"PRIsVALUE" with %"PRIsVALUE" failed",
              rb_obj_class(x), classname);
 }
 
+void
+rb_cmperr_reason(VALUE x, VALUE y, const char *reason)
+{
+    VALUE classname = cmperr_subject(y);
+    rb_raise(rb_eArgError, "comparison of %"PRIsVALUE" with %"PRIsVALUE" failed: %s",
+             rb_obj_class(x), classname, reason);
+}
+
 static VALUE
 invcmp_recursive(VALUE x, VALUE y, int recursive)
 {
diff --git a/configure.ac b/configure.ac
index 05e2e9aca26ddf..1b59942463bad6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -715,7 +715,7 @@ AS_IF([test "$fdeclspec" = yes], [
     RUBY_APPEND_OPTIONS(cflags, -fdeclspec)
     RUBY_APPEND_OPTIONS(orig_cflags, -fdeclspec)
 ])
-RUBY_TRY_CXXFLAGS(-fdeclspec, [fdeclspec=yes], [fdeclspec=no])
+RUBY_TRY_CXXFLAGS(-fdeclspec, [fdeclspec=yes], [fdeclspec=no], [@%:@include <cstdio>])
 AS_IF([test "$fdeclspec" = yes], [
     RUBY_APPEND_OPTIONS(CXXFLAGS, -fdeclspec)
 ])
diff --git a/depend b/depend
index ced1dfd6ad8a75..f04e40e16f705d 100644
--- a/depend
+++ b/depend
@@ -287,6 +287,7 @@ ast.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 ast.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 ast.$(OBJEXT): $(top_srcdir)/internal/bits.h
 ast.$(OBJEXT): $(top_srcdir)/internal/box.h
+ast.$(OBJEXT): $(top_srcdir)/internal/compar.h
 ast.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 ast.$(OBJEXT): $(top_srcdir)/internal/complex.h
 ast.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
@@ -530,6 +531,7 @@ bignum.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/bits.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/box.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/class.h
+bignum.$(OBJEXT): $(top_srcdir)/internal/compar.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/complex.h
 bignum.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
@@ -1627,6 +1629,7 @@ compile.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 compile.$(OBJEXT): $(top_srcdir)/internal/bits.h
 compile.$(OBJEXT): $(top_srcdir)/internal/box.h
 compile.$(OBJEXT): $(top_srcdir)/internal/class.h
+compile.$(OBJEXT): $(top_srcdir)/internal/compar.h
 compile.$(OBJEXT): $(top_srcdir)/internal/compile.h
 compile.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 compile.$(OBJEXT): $(top_srcdir)/internal/complex.h
@@ -1895,6 +1898,7 @@ complex.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 complex.$(OBJEXT): $(top_srcdir)/internal/bits.h
 complex.$(OBJEXT): $(top_srcdir)/internal/box.h
 complex.$(OBJEXT): $(top_srcdir)/internal/class.h
+complex.$(OBJEXT): $(top_srcdir)/internal/compar.h
 complex.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 complex.$(OBJEXT): $(top_srcdir)/internal/complex.h
 complex.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -4885,6 +4889,7 @@ enumerator.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/bits.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/box.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/class.h
+enumerator.$(OBJEXT): $(top_srcdir)/internal/compar.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/enumerator.h
 enumerator.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -5815,6 +5820,7 @@ gc.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 gc.$(OBJEXT): $(top_srcdir)/internal/bits.h
 gc.$(OBJEXT): $(top_srcdir)/internal/box.h
 gc.$(OBJEXT): $(top_srcdir)/internal/class.h
+gc.$(OBJEXT): $(top_srcdir)/internal/compar.h
 gc.$(OBJEXT): $(top_srcdir)/internal/compile.h
 gc.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 gc.$(OBJEXT): $(top_srcdir)/internal/complex.h
@@ -6966,6 +6972,7 @@ io.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 io.$(OBJEXT): $(top_srcdir)/internal/bits.h
 io.$(OBJEXT): $(top_srcdir)/internal/box.h
 io.$(OBJEXT): $(top_srcdir)/internal/class.h
+io.$(OBJEXT): $(top_srcdir)/internal/compar.h
 io.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 io.$(OBJEXT): $(top_srcdir)/internal/encoding.h
 io.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -7197,6 +7204,7 @@ io_buffer.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/bits.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/box.h
+io_buffer.$(OBJEXT): $(top_srcdir)/internal/compar.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/error.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
@@ -7413,6 +7421,7 @@ iseq.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/bits.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/box.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/class.h
+iseq.$(OBJEXT): $(top_srcdir)/internal/compar.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/compile.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 iseq.$(OBJEXT): $(top_srcdir)/internal/complex.h
@@ -7919,6 +7928,7 @@ load.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 load.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 load.$(OBJEXT): $(top_srcdir)/internal/bits.h
 load.$(OBJEXT): $(top_srcdir)/internal/box.h
+load.$(OBJEXT): $(top_srcdir)/internal/compar.h
 load.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 load.$(OBJEXT): $(top_srcdir)/internal/complex.h
 load.$(OBJEXT): $(top_srcdir)/internal/dir.h
@@ -8675,6 +8685,7 @@ marshal.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/bits.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/box.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/class.h
+marshal.$(OBJEXT): $(top_srcdir)/internal/compar.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/encoding.h
 marshal.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -9284,6 +9295,7 @@ miniinit.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/bits.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/box.h
+miniinit.$(OBJEXT): $(top_srcdir)/internal/compar.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/complex.h
 miniinit.$(OBJEXT): $(top_srcdir)/internal/eval.h
@@ -9757,6 +9769,7 @@ node_dump.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/bits.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/box.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/class.h
+node_dump.$(OBJEXT): $(top_srcdir)/internal/compar.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/complex.h
 node_dump.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
@@ -9974,6 +9987,7 @@ numeric.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/bits.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/box.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/class.h
+numeric.$(OBJEXT): $(top_srcdir)/internal/compar.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/complex.h
 numeric.$(OBJEXT): $(top_srcdir)/internal/enumerator.h
@@ -10196,6 +10210,7 @@ object.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 object.$(OBJEXT): $(top_srcdir)/internal/bits.h
 object.$(OBJEXT): $(top_srcdir)/internal/box.h
 object.$(OBJEXT): $(top_srcdir)/internal/class.h
+object.$(OBJEXT): $(top_srcdir)/internal/compar.h
 object.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 object.$(OBJEXT): $(top_srcdir)/internal/error.h
 object.$(OBJEXT): $(top_srcdir)/internal/eval.h
@@ -10424,6 +10439,7 @@ pack.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 pack.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 pack.$(OBJEXT): $(top_srcdir)/internal/bits.h
 pack.$(OBJEXT): $(top_srcdir)/internal/box.h
+pack.$(OBJEXT): $(top_srcdir)/internal/compar.h
 pack.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 pack.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
 pack.$(OBJEXT): $(top_srcdir)/internal/gc.h
@@ -10640,6 +10656,7 @@ parse.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 parse.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 parse.$(OBJEXT): $(top_srcdir)/internal/bits.h
 parse.$(OBJEXT): $(top_srcdir)/internal/box.h
+parse.$(OBJEXT): $(top_srcdir)/internal/compar.h
 parse.$(OBJEXT): $(top_srcdir)/internal/compile.h
 parse.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 parse.$(OBJEXT): $(top_srcdir)/internal/complex.h
@@ -12680,6 +12697,7 @@ process.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 process.$(OBJEXT): $(top_srcdir)/internal/bits.h
 process.$(OBJEXT): $(top_srcdir)/internal/box.h
 process.$(OBJEXT): $(top_srcdir)/internal/class.h
+process.$(OBJEXT): $(top_srcdir)/internal/compar.h
 process.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 process.$(OBJEXT): $(top_srcdir)/internal/dir.h
 process.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -12912,6 +12930,7 @@ ractor.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/bits.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/box.h
+ractor.$(OBJEXT): $(top_srcdir)/internal/compar.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/complex.h
 ractor.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -13145,6 +13164,7 @@ random.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 random.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 random.$(OBJEXT): $(top_srcdir)/internal/bits.h
 random.$(OBJEXT): $(top_srcdir)/internal/box.h
+random.$(OBJEXT): $(top_srcdir)/internal/compar.h
 random.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 random.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
 random.$(OBJEXT): $(top_srcdir)/internal/gc.h
@@ -13557,6 +13577,7 @@ rational.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 rational.$(OBJEXT): $(top_srcdir)/internal/bits.h
 rational.$(OBJEXT): $(top_srcdir)/internal/box.h
 rational.$(OBJEXT): $(top_srcdir)/internal/class.h
+rational.$(OBJEXT): $(top_srcdir)/internal/compar.h
 rational.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 rational.$(OBJEXT): $(top_srcdir)/internal/complex.h
 rational.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -14990,6 +15011,7 @@ ruby.$(OBJEXT): $(top_srcdir)/internal/bits.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/box.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/class.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/cmdlineopt.h
+ruby.$(OBJEXT): $(top_srcdir)/internal/compar.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/complex.h
 ruby.$(OBJEXT): $(top_srcdir)/internal/cont.h
@@ -15239,8 +15261,10 @@ ruby.$(OBJEXT): {$(VPATH)}vm_opts.h
 ruby.$(OBJEXT): {$(VPATH)}yjit.h
 ruby_parser.$(OBJEXT): $(hdrdir)/ruby/ruby.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/array.h
+ruby_parser.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/bits.h
+ruby_parser.$(OBJEXT): $(top_srcdir)/internal/compar.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/complex.h
 ruby_parser.$(OBJEXT): $(top_srcdir)/internal/error.h
@@ -16445,9 +16469,11 @@ signal.$(OBJEXT): {$(VPATH)}vm_debug.h
 signal.$(OBJEXT): {$(VPATH)}vm_opts.h
 sprintf.$(OBJEXT): $(hdrdir)/ruby/ruby.h
 sprintf.$(OBJEXT): $(hdrdir)/ruby/version.h
+sprintf.$(OBJEXT): $(top_srcdir)/internal/basic_operators.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/bits.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/class.h
+sprintf.$(OBJEXT): $(top_srcdir)/internal/compar.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/error.h
 sprintf.$(OBJEXT): $(top_srcdir)/internal/fixnum.h
@@ -20475,6 +20501,7 @@ yjit.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/bits.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/box.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/class.h
+yjit.$(OBJEXT): $(top_srcdir)/internal/compar.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/compile.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 yjit.$(OBJEXT): $(top_srcdir)/internal/cont.h
@@ -20732,6 +20759,7 @@ zjit.$(OBJEXT): $(top_srcdir)/internal/bignum.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/bits.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/box.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/class.h
+zjit.$(OBJEXT): $(top_srcdir)/internal/compar.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/compile.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 zjit.$(OBJEXT): $(top_srcdir)/internal/cont.h
diff --git a/ext/-test-/integer/depend b/ext/-test-/integer/depend
index 0ea007e814128d..d0589b5e5dd8a8 100644
--- a/ext/-test-/integer/depend
+++ b/ext/-test-/integer/depend
@@ -159,8 +159,11 @@ core_ext.o: $(hdrdir)/ruby/missing.h
 core_ext.o: $(hdrdir)/ruby/ruby.h
 core_ext.o: $(hdrdir)/ruby/st.h
 core_ext.o: $(hdrdir)/ruby/subst.h
+core_ext.o: $(top_srcdir)/internal.h
+core_ext.o: $(top_srcdir)/internal/basic_operators.h
 core_ext.o: $(top_srcdir)/internal/bignum.h
 core_ext.o: $(top_srcdir)/internal/bits.h
+core_ext.o: $(top_srcdir)/internal/compar.h
 core_ext.o: $(top_srcdir)/internal/compilers.h
 core_ext.o: $(top_srcdir)/internal/fixnum.h
 core_ext.o: $(top_srcdir)/internal/numeric.h
diff --git a/ext/-test-/rational/depend b/ext/-test-/rational/depend
index 56d6ab77d6c36a..d949fca66bcc88 100644
--- a/ext/-test-/rational/depend
+++ b/ext/-test-/rational/depend
@@ -163,8 +163,11 @@ rat.o: $(hdrdir)/ruby/missing.h
 rat.o: $(hdrdir)/ruby/ruby.h
 rat.o: $(hdrdir)/ruby/st.h
 rat.o: $(hdrdir)/ruby/subst.h
+rat.o: $(top_srcdir)/internal.h
+rat.o: $(top_srcdir)/internal/basic_operators.h
 rat.o: $(top_srcdir)/internal/bignum.h
 rat.o: $(top_srcdir)/internal/bits.h
+rat.o: $(top_srcdir)/internal/compar.h
 rat.o: $(top_srcdir)/internal/compilers.h
 rat.o: $(top_srcdir)/internal/fixnum.h
 rat.o: $(top_srcdir)/internal/gc.h
diff --git a/ext/ripper/depend b/ext/ripper/depend
index 944da25ee94f38..96d41c87b89ac0 100644
--- a/ext/ripper/depend
+++ b/ext/ripper/depend
@@ -586,6 +586,7 @@ ripper.o: $(top_srcdir)/internal/basic_operators.h
 ripper.o: $(top_srcdir)/internal/bignum.h
 ripper.o: $(top_srcdir)/internal/bits.h
 ripper.o: $(top_srcdir)/internal/box.h
+ripper.o: $(top_srcdir)/internal/compar.h
 ripper.o: $(top_srcdir)/internal/compile.h
 ripper.o: $(top_srcdir)/internal/compilers.h
 ripper.o: $(top_srcdir)/internal/complex.h
@@ -812,8 +813,10 @@ ripper_init.o: $(hdrdir)/ruby/st.h
 ripper_init.o: $(hdrdir)/ruby/subst.h
 ripper_init.o: $(top_srcdir)/internal.h
 ripper_init.o: $(top_srcdir)/internal/array.h
+ripper_init.o: $(top_srcdir)/internal/basic_operators.h
 ripper_init.o: $(top_srcdir)/internal/bignum.h
 ripper_init.o: $(top_srcdir)/internal/bits.h
+ripper_init.o: $(top_srcdir)/internal/compar.h
 ripper_init.o: $(top_srcdir)/internal/compilers.h
 ripper_init.o: $(top_srcdir)/internal/complex.h
 ripper_init.o: $(top_srcdir)/internal/fixnum.h
diff --git a/internal/compar.h b/internal/compar.h
index 9115e4bd63a8e4..5eb5e8714e7483 100644
--- a/internal/compar.h
+++ b/internal/compar.h
@@ -25,5 +25,6 @@
 
 /* compar.c */
 VALUE rb_invcmp(VALUE, VALUE);
+NORETURN(void rb_cmperr_reason(VALUE, VALUE, const char*));
 
 #endif /* INTERNAL_COMPAR_H */
diff --git a/internal/numeric.h b/internal/numeric.h
index 6391b1e9bc0f5c..280c008952ed7d 100644
--- a/internal/numeric.h
+++ b/internal/numeric.h
@@ -10,9 +10,9 @@
  */
 #include "internal/bignum.h"    /* for BIGNUM_POSITIVE_P */
 #include "internal/bits.h"      /* for RUBY_BIT_ROTL */
+#include "internal/compar.h"    /* for rb_cmperr_reason */
 #include "internal/fixnum.h"    /* for FIXNUM_POSITIVE_P */
 #include "internal/vm.h"        /* for rb_method_basic_definition_p */
-#include "ruby/intern.h"        /* for rb_cmperr */
 #include "ruby/ruby.h"          /* for USE_FLONUM */
 
 #define ROUND_TO(mode, even, up, down) \
@@ -210,7 +210,7 @@ rb_num_compare_with_zero(VALUE num, ID mid)
     VALUE zero = INT2FIX(0);
     VALUE r = rb_check_funcall(num, mid, 1, &zero);
     if (RB_UNDEF_P(r)) {
-        rb_cmperr(num, zero);
+        rb_cmperr_reason(num, zero, "unable to compare with zero");
     }
     return r;
 }
diff --git a/numeric.c b/numeric.c
index 10ce7358e7a370..226a47f7b8f38b 100644
--- a/numeric.c
+++ b/numeric.c
@@ -492,7 +492,7 @@ rb_num_coerce_cmp(VALUE x, VALUE y, ID func)
 static VALUE
 ensure_cmp(VALUE c, VALUE x, VALUE y)
 {
-    if (NIL_P(c)) rb_cmperr(x, y);
+    if (NIL_P(c)) rb_cmperr_reason(x, y, "comparator returned nil");
     return c;
 }
 
@@ -502,7 +502,7 @@ rb_num_coerce_relop(VALUE x, VALUE y, ID func)
     VALUE x0 = x, y0 = y;
 
     if (!do_coerce(&x, &y, FALSE)) {
-        rb_cmperr(x0, y0);
+        rb_cmperr_reason(x0, y0, "coercion was not possible");
         UNREACHABLE_RETURN(Qnil);
     }
     return ensure_cmp(rb_funcall(x, func, 1, y), x0, y0);
@@ -5911,7 +5911,7 @@ int_downto(VALUE from, VALUE to)
             rb_yield(i);
             i = rb_funcall(i, '-', 1, INT2FIX(1));
         }
-        if (NIL_P(c)) rb_cmperr(i, to);
+        ensure_cmp(c, i, to);
     }
     return from;
 }
diff --git a/range.c b/range.c
index c3b3813cb1eef7..041cd93f73ee4e 100644
--- a/range.c
+++ b/range.c
@@ -200,11 +200,10 @@ range_eq(VALUE range, VALUE obj)
 static int
 r_less(VALUE a, VALUE b)
 {
-    VALUE r = rb_funcall(a, id_cmp, 1, b);
-
-    if (NIL_P(r))
-        return INT_MAX;
-    return rb_cmpint(r, a, b);
+    VALUE r;
+#define rb_cmpint(cmp, a, b) (NIL_P(r = (cmp)) ? INT_MAX : rb_cmpint(r, (a), (b)))
+    return OPTIMIZED_CMP(a, b);
+#undef rb_cmpint
 }
 
 static VALUE
diff --git a/spec/ruby/core/comparable/lt_spec.rb b/spec/ruby/core/comparable/lt_spec.rb
index bca95f8d252bce..3c73e410ea14ed 100644
--- a/spec/ruby/core/comparable/lt_spec.rb
+++ b/spec/ruby/core/comparable/lt_spec.rb
@@ -43,7 +43,7 @@
 
   it "raises an argument error with a message containing the value" do
     -> { ("foo" < 7) }.should raise_error(ArgumentError) { |e|
-      e.message.should == "comparison of String with 7 failed"
+      e.message.should.include? "String with 7 failed"
     }
   end
 end
diff --git a/test/rubygems/test_gem_commands_push_command.rb b/test/rubygems/test_gem_commands_push_command.rb
index 1477a749471443..978ed3ada88e8c 100644
--- a/test/rubygems/test_gem_commands_push_command.rb
+++ b/test/rubygems/test_gem_commands_push_command.rb
@@ -487,6 +487,7 @@ def test_with_webauthn_enabled_success
   end
 
   def test_with_webauthn_enabled_failure
+    pend "Flaky on TruffleRuby" if RUBY_ENGINE == "truffleruby"
     response_success = "Successfully registered gem: freewill (1.0.0)"
     server = Gem::MockTCPServer.new
     error = Gem::WebauthnVerificationError.new("Something went wrong")
diff --git a/zjit/src/hir.rs b/zjit/src/hir.rs
index a71946b3c915e3..3382747db71353 100644
--- a/zjit/src/hir.rs
+++ b/zjit/src/hir.rs
@@ -5318,6 +5318,28 @@ impl Function {
         }
     }
 
+    /// Remove duplicate CheckInterrupts instructions within each basic block.
+    /// Only the first CheckInterrupts in a block is needed unless an intervening
+    /// instruction writes to InterruptFlag (e.g. a call), which resets tracking.
+    fn remove_duplicate_check_interrupts(&mut self) {
+        for block_id in self.rpo() {
+            let mut seen = false;
+            let insns = std::mem::take(&mut self.blocks[block_id.0].insns);
+            let mut new_insns = Vec::with_capacity(insns.len());
+            for insn_id in insns {
+                let insn = &self.insns[insn_id.0];
+                if matches!(insn, Insn::CheckInterrupts { .. }) {
+                    if seen { continue; }
+                    seen = true;
+                } else if insn.effects_of().write_bits().overlaps(abstract_heaps::InterruptFlag) {
+                    seen = false;
+                }
+                new_insns.push(insn_id);
+            }
+            self.blocks[block_id.0].insns = new_insns;
+        }
+    }
+
     /// Return a list that has entry_block and then jit_entry_blocks
     fn entry_blocks(&self) -> Vec<BlockId> {
         let mut entry_blocks = self.jit_entry_blocks.clone();
@@ -5545,6 +5567,8 @@ impl Function {
                     Counter::compile_hir_clean_cfg_time_ns
                 } else if ident_equal!($name, remove_redundant_patch_points) {
                     Counter::compile_hir_remove_redundant_patch_points_time_ns
+                } else if ident_equal!($name, remove_duplicate_check_interrupts) {
+                    Counter::compile_hir_remove_duplicate_check_interrupts_time_ns
                 } else if ident_equal!($name, eliminate_dead_code) {
                     Counter::compile_hir_eliminate_dead_code_time_ns
                 } else {
@@ -5573,6 +5597,7 @@ impl Function {
         run_pass!(fold_constants);
         run_pass!(clean_cfg);
         run_pass!(remove_redundant_patch_points);
+        run_pass!(remove_duplicate_check_interrupts);
         run_pass!(eliminate_dead_code);
 
         if should_dump {
diff --git a/zjit/src/hir/opt_tests.rs b/zjit/src/hir/opt_tests.rs
index 239e3c65949860..440d8a5d17d83a 100644
--- a/zjit/src/hir/opt_tests.rs
+++ b/zjit/src/hir/opt_tests.rs
@@ -53,9 +53,7 @@ mod hir_opt_tests {
         bb3(v8:BasicObject, v9:NilClass):
           v13:TrueClass = Const Value(true)
           CheckInterrupts
-          v22:TrueClass = RefineType v13, Truthy
           v25:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v25
         ");
     }
@@ -87,9 +85,7 @@ mod hir_opt_tests {
         bb3(v8:BasicObject, v9:NilClass):
           v13:FalseClass = Const Value(false)
           CheckInterrupts
-          v20:FalseClass = RefineType v13, Falsy
           v35:Fixnum[4] = Const Value(4)
-          CheckInterrupts
           Return v35
         ");
     }
@@ -681,7 +677,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v24:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v24
         ");
     }
@@ -714,11 +709,8 @@ mod hir_opt_tests {
           v60:TrueClass = Const Value(true)
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
-          v62:TrueClass = Const Value(true)
           IncrCounter inline_cfunc_optimized_send_count
-          CheckInterrupts
           v37:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v37
         ");
     }
@@ -752,7 +744,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v24:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v24
         ");
     }
@@ -785,11 +776,8 @@ mod hir_opt_tests {
           v60:TrueClass = Const Value(true)
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
-          v62:TrueClass = Const Value(true)
           IncrCounter inline_cfunc_optimized_send_count
-          CheckInterrupts
           v37:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v37
         ");
     }
@@ -823,7 +811,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v33:Fixnum[4] = Const Value(4)
-          CheckInterrupts
           Return v33
         ");
     }
@@ -857,7 +844,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v24:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v24
         ");
     }
@@ -892,7 +878,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v24:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v24
         ");
     }
@@ -927,7 +912,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v33:Fixnum[4] = Const Value(4)
-          CheckInterrupts
           Return v33
         ");
     }
@@ -4283,7 +4267,6 @@ mod hir_opt_tests {
           v50:NilClass = Const Value(nil)
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
-          CheckInterrupts
           Return v46
         ");
     }
@@ -4321,7 +4304,6 @@ mod hir_opt_tests {
           PatchPoint MethodRedefined(C@0x1008, initialize@0x1038, cme:0x1040)
           v52:BasicObject = SendDirect v49, 0x1068, :initialize (0x1078), v15
           CheckInterrupts
-          CheckInterrupts
           Return v49
         ");
     }
@@ -4354,7 +4336,6 @@ mod hir_opt_tests {
           v50:NilClass = Const Value(nil)
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
-          CheckInterrupts
           Return v46
         ");
     }
@@ -4387,7 +4368,6 @@ mod hir_opt_tests {
           v50:NilClass = Const Value(nil)
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
-          CheckInterrupts
           Return v46
         ");
     }
@@ -4418,7 +4398,6 @@ mod hir_opt_tests {
           IncrCounter complex_arg_pass_param_block
           v19:BasicObject = Send v46, :initialize # SendFallbackReason: Complex argument passing
           CheckInterrupts
-          CheckInterrupts
           Return v46
         ");
         assert_snapshot!(inspect("test"), @"{}");
@@ -4483,7 +4462,6 @@ mod hir_opt_tests {
           v49:SetExact = GuardType v17, SetExact
           v50:BasicObject = CCallVariadic v49, :Set#initialize@0x1068
           CheckInterrupts
-          CheckInterrupts
           Return v17
         ");
     }
@@ -4547,7 +4525,6 @@ mod hir_opt_tests {
           PatchPoint MethodRedefined(Regexp@0x1008, initialize@0x1048, cme:0x1050)
           v54:BasicObject = CCallVariadic v50, :Regexp#initialize@0x1078, v16
           CheckInterrupts
-          CheckInterrupts
           Return v50
         ");
     }
@@ -5914,7 +5891,6 @@ mod hir_opt_tests {
           v13:NilClass = Const Value(nil)
           CheckInterrupts
           v21:NilClass = Const Value(nil)
-          CheckInterrupts
           Return v21
         ");
     }
@@ -5946,7 +5922,6 @@ mod hir_opt_tests {
           v23:Fixnum[1] = RefineType v13, NotNil
           PatchPoint MethodRedefined(Integer@0x1000, itself@0x1008, cme:0x1010)
           IncrCounter inline_cfunc_optimized_send_count
-          CheckInterrupts
           Return v23
         ");
     }
@@ -12110,7 +12085,6 @@ mod hir_opt_tests {
           IncrCounter inline_cfunc_optimized_send_count
           CheckInterrupts
           v26:StaticSymbol[:CORRECT] = Const Value(VALUE(0x10a8))
-          CheckInterrupts
           Return v26
         ");
     }
@@ -13509,11 +13483,7 @@ mod hir_opt_tests {
           IfFalse v16, bb6(v9, v17)
           v19:Truthy = RefineType v10, Truthy
           CheckInterrupts
-          v27:Truthy = RefineType v19, Truthy
-          CheckInterrupts
-          v35:Truthy = RefineType v27, Truthy
           v38:Fixnum[3] = Const Value(3)
-          CheckInterrupts
           Return v38
         bb6(v43:BasicObject, v44:Falsy):
           v48:Fixnum[6] = Const Value(6)
diff --git a/zjit/src/stats.rs b/zjit/src/stats.rs
index 42dd39fdd047e9..aca4ae8051657b 100644
--- a/zjit/src/stats.rs
+++ b/zjit/src/stats.rs
@@ -171,6 +171,7 @@ make_counters! {
         compile_hir_fold_constants_time_ns,
         compile_hir_clean_cfg_time_ns,
         compile_hir_remove_redundant_patch_points_time_ns,
+        compile_hir_remove_duplicate_check_interrupts_time_ns,
         compile_hir_eliminate_dead_code_time_ns,
         compile_lir_time_ns,
     }