[Arc] Fix dominance issue in GroupResetsAndEnables #5511
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maerhart
approved these changes
Jun 28, 2023
| @@ -166,7 +165,8 @@ struct GroupAssignmentsInIfPattern : public OpRewritePattern<scf::IfOp> { | |||
| // Skip anything not in a ClockTreeOp | |||
| auto clockTreeOp = ifOp->getParentOfType<ClockTreeOp>(); | |||
| if (!clockTreeOp) | |||
| return failure(); | |||
| // This probably means the design uses a derived clock (warning). | |||
| return success(false); | |||
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This is exactly equivalent to return failure() (see implementation in LogicalResult.h), so no need to change.
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Oh thanks, I ran into an issue where the compiler was failing without displaying an error during debugging and thought it was because of this, but it must have been something else related to the dominance stuff. I undid that change, thanks for the catch!
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I see. That might be because no failure is returned in line 207 (also no error message). Thanks for the catch!
calebmkim
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Jul 12, 2023
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This fixes a dominance issue that can occur in GroupResetsAndEnables. Unfortunately I haven't been able to reduce the test case from a larger design (tried using circt-reduce).
There are two fixes:
definition->getUsers()to check for dominance, sincedefinitionis the operation that will actually be moved. If it generates multiple results, the place it is being moved to must dominate all those results, not just the operand used in the block.