Drew Wock 161d927dda [SeparateConstOffsetFromGEP] Fix: sext(a) + sext(b) -> sext(a + b) matches add and sub instructions with one another ... During the SeparateConstOffsetFromGEP pass, signed extensions are distributed to the values that feed into them and then later recombined. The recombination stage is somewhat problematic- it doesn't differ add and sub instructions from another when matching the sext(a) +/- sext(b) -> sext(a +/- b) pattern in some instances. An example- the IR contains: %unextendedA %unextendedB %subuAuB = unextendedA - unextendedB %extA = extend A %extB = extend B %addeAeB = extA + extB The problematic optimization will transform that into: %unextendedA %unextendedB %subuAuB = unextendedA - unextendedB %extA = extend A %extB = extend B %addeAeB = extend subuAuB ; Obviously not semantically equivalent to the IR input. This patch fixes that. Patch by Drew Wock <drew.wock@sas.com> Differential Revision: https://reviews.llvm.org/D65967		2020-01-17 12:22:52 -05:00
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AMDGPU
NVPTX
test-add-sub-separation.ll	[SeparateConstOffsetFromGEP] Fix: sext(a) + sext(b) -> sext(a + b) matches add and sub instructions with one another	2020-01-17 12:22:52 -05:00