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Imported from GitHub PR #39413 📝 Summary of Changes Added `VLOG(2)` debugging statements to `xla/service/instruction_fusion.cc`. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in the `ShouldFuse` decision. 🎯 Justification This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions. 🚀 Kind of Contribution ✨ New Feature, ♻️ Cleanup 📊 Benchmark (for Performance Improvements) N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed. 🧪 Unit Tests: No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly: Ran bazelisk test //xla/service:instruction_fusion_test Verified log output manually. 🧪 Execution Tests: N/A - This is a logging-only change and does not affect execution correctness or hardware backends. Copybara import of the project: -- 0840683 by complexbulb <personal123888@googlemail.com>: Add VLOG for root instruction fusion rejection -- 19bf0ac by complexbulb <personal123888@googlemail.com>: Add VLOG debugging for fusion pass decisions Merging this change closes #39413 FUTURE_COPYBARA_INTEGRATE_REVIEW=#39413 from complexbulb:add-fusion-debug-logging 19bf0ac PiperOrigin-RevId: 886056117
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Imported from GitHub PR openxla/xla#39413 📝 Summary of Changes Added `VLOG(2)` debugging statements to `xla/service/instruction_fusion.cc`. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in the `ShouldFuse` decision. 🎯 Justification This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions. 🚀 Kind of Contribution ✨ New Feature, ♻️ Cleanup 📊 Benchmark (for Performance Improvements) N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed. 🧪 Unit Tests: No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly: Ran bazelisk test //xla/service:instruction_fusion_test Verified log output manually. 🧪 Execution Tests: N/A - This is a logging-only change and does not affect execution correctness or hardware backends. Copybara import of the project: -- 0840683c70bf90e85912d78942e98f9668d95524 by complexbulb <personal123888@googlemail.com>: Add VLOG for root instruction fusion rejection -- 19bf0ac838b695157f9ff2f41bab7ba29bcd45b2 by complexbulb <personal123888@googlemail.com>: Add VLOG debugging for fusion pass decisions Merging this change closes #39413 FUTURE_COPYBARA_INTEGRATE_REVIEW=openxla/xla#39413 from complexbulb:add-fusion-debug-logging 19bf0ac838b695157f9ff2f41bab7ba29bcd45b2 PiperOrigin-RevId: 886056117
copybara-service Bot
pushed a commit
that referenced
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Mar 19, 2026
Imported from GitHub PR #39413 📝 Summary of Changes Added `VLOG(2)` debugging statements to `xla/service/instruction_fusion.cc`. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in the `ShouldFuse` decision. 🎯 Justification This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions. 🚀 Kind of Contribution ✨ New Feature, ♻️ Cleanup 📊 Benchmark (for Performance Improvements) N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed. 🧪 Unit Tests: No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly: Ran bazelisk test //xla/service:instruction_fusion_test Verified log output manually. 🧪 Execution Tests: N/A - This is a logging-only change and does not affect execution correctness or hardware backends. Copybara import of the project: -- 0840683 by complexbulb <personal123888@googlemail.com>: Add VLOG for root instruction fusion rejection -- 19bf0ac by complexbulb <personal123888@googlemail.com>: Add VLOG debugging for fusion pass decisions Merging this change closes #39413 FUTURE_COPYBARA_INTEGRATE_REVIEW=#39413 from complexbulb:add-fusion-debug-logging 19bf0ac PiperOrigin-RevId: 886056117
copybara-service Bot
pushed a commit
to tensorflow/tensorflow
that referenced
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Mar 19, 2026
Imported from GitHub PR openxla/xla#39413 📝 Summary of Changes Added `VLOG(2)` debugging statements to `xla/service/instruction_fusion.cc`. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in the `ShouldFuse` decision. 🎯 Justification This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions. 🚀 Kind of Contribution ✨ New Feature, ♻️ Cleanup 📊 Benchmark (for Performance Improvements) N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed. 🧪 Unit Tests: No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly: Ran bazelisk test //xla/service:instruction_fusion_test Verified log output manually. 🧪 Execution Tests: N/A - This is a logging-only change and does not affect execution correctness or hardware backends. Copybara import of the project: -- 0840683c70bf90e85912d78942e98f9668d95524 by complexbulb <personal123888@googlemail.com>: Add VLOG for root instruction fusion rejection -- 19bf0ac838b695157f9ff2f41bab7ba29bcd45b2 by complexbulb <personal123888@googlemail.com>: Add VLOG debugging for fusion pass decisions Merging this change closes #39413 FUTURE_COPYBARA_INTEGRATE_REVIEW=openxla/xla#39413 from complexbulb:add-fusion-debug-logging 19bf0ac838b695157f9ff2f41bab7ba29bcd45b2 PiperOrigin-RevId: 886056117
copybara-service Bot
pushed a commit
to tensorflow/tensorflow
that referenced
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Mar 19, 2026
Imported from GitHub PR openxla/xla#39413 📝 Summary of Changes Added `VLOG(2)` debugging statements to `xla/service/instruction_fusion.cc`. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in the `ShouldFuse` decision. 🎯 Justification This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions. 🚀 Kind of Contribution ✨ New Feature, ♻️ Cleanup 📊 Benchmark (for Performance Improvements) N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed. 🧪 Unit Tests: No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly: Ran bazelisk test //xla/service:instruction_fusion_test Verified log output manually. 🧪 Execution Tests: N/A - This is a logging-only change and does not affect execution correctness or hardware backends. Copybara import of the project: -- 0840683c70bf90e85912d78942e98f9668d95524 by complexbulb <personal123888@googlemail.com>: Add VLOG for root instruction fusion rejection -- 19bf0ac838b695157f9ff2f41bab7ba29bcd45b2 by complexbulb <personal123888@googlemail.com>: Add VLOG debugging for fusion pass decisions Merging this change closes #39413 PiperOrigin-RevId: 886174965
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📝 Summary of Changes
Added
VLOG(2)debugging statements toxla/service/instruction_fusion.cc. The logs explicitly output fusion rejections as well as the specific reason for rejection. The logs now surface the exact names of the producer and consumer instructions involved in theShouldFusedecision.🎯 Justification
This change improves debuggability and compiler observability. Previously, it was tedious to trace exactly why specific instructions in a large HLO graph were not fused. By gating this behind VLOG, developers can now trace exact fusion logic and graph decisions.
🚀 Kind of Contribution
✨ New Feature, ♻️ Cleanup
📊 Benchmark (for Performance Improvements)
N/A - This PR only introduces developer logging and does not affect compiler performance or execution speed.
🧪 Unit Tests:
No new unit tests were required as this does not change compilation semantics. Verified that existing tests pass cleanly:
Ran bazelisk test //xla/service:instruction_fusion_test
Verified log output manually.
🧪 Execution Tests:
N/A - This is a logging-only change and does not affect execution correctness or hardware backends.