[CodeGenPrepare] Return false in AddressingModeMatcher::matchOperationAddr if zext has nneg flag #72098
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…nAddr if zext has nneg flag Fix llvm#72046
nikic
requested changes
Nov 13, 2023
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This isn't the right fix. Instead, there should be a dropPoisonGeneratingFlags() call at the point where the zext operand is updated. The code is pretty convoluted, but I think this happens inside this method:
llvm-project/llvm/lib/CodeGen/CodeGenPrepare.cpp
Line 4529 in b0d3641
Also, this PR is missing a test.
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I've proposed a possible alternative at #72103. Instead of dropping the flag, we can avoid reusing the instruction in the first place. |
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@nikic Thanks, I will close this PR. |
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Fix #72046