[PATCH] D36234: [InstCombine] Support sext in foldLogicCastConstant

[Sanjay Patel via Phabricator via llvm-commits]

spatel accepted this revision.
spatel added a comment.
This revision is now accepted and ready to land.

LGTM. I think it makes sense for the same reason as the zext case.



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Comment at: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:1092
 
   // Move the logic operation ahead of a zext if the constant is unchanged in
   // the smaller source type. Performing the logic in a smaller type may provide
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Update comment to 'zext or sext'.


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Comment at: test/Transforms/InstCombine/cast.ll:591-592
+; CHECK-NEXT:    [[TMP1:%.*]] = or i8 [[A:%.*]], 42
+; CHECK-NEXT:    [[C:%.*]] = sext i8 [[TMP1]] to i64
+; CHECK-NEXT:    [[E:%.*]] = and i64 [[C]], 4294967295
 ; CHECK-NEXT:    ret i64 [[E]]
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Not this patch, but seems odd that we'd choose to sext to the larger type and mask rather than sext+zext?


https://reviews.llvm.org/D36234