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Backports #132
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Backports #132
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The test file shows a case where the avoid store forwarding block pass misses to copy a range (-1..1) when the load displacement changes sign. Baseline test for D55485. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348712 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes https://bugs.llvm.org/show_bug.cgi?id=39926. The size of the first copy was computed as std::abs(std::abs(LdDisp2) - std::abs(LdDisp1)), which results in skipped bytes if the signs of LdDisp2 and LdDisp1 differ. As far as I can see, this should just be LdDisp2 - LdDisp1. The case where LdDisp1 > LdDisp2 is already handled in the code above, in which case LdDisp2 is set to LdDisp1 and this subtraction will evaluate to Size1 = 0, which is the correct value to skip an overlapping copy. Differential Revision: https://reviews.llvm.org/D55485 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348750 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes https://bugs.llvm.org/show_bug.cgi?id=39908. The evaluateGEPOffsetExpression() function simplifies GEP offsets for use in comparisons against zero, basically by converting X*Scale+Offset==0 to X+Offset/Scale==0 if Scale divides Offset. However, before this is done, Offset is masked down to the pointer size. This results in incorrect results for negative Offsets, because we basically end up dividing the 32-bit offset *zero* extended to 64-bit bits (rather than sign extended). Fix this by explicitly sign extending the truncated value. Differential Revision: https://reviews.llvm.org/D55449 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348987 91177308-0d34-0410-b5e6-96231b3b80d8
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Backports fixes for two miscompiles: