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| author | Sanjay Patel <spatel@rotateright.com> | 2017-02-18 22:20:09 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-02-18 22:20:09 +0000 |
| commit | 53c5c3d65df3d48fd147b7786ef56cf9da6548d2 (patch) | |
| tree | 0289773ebb088597a27473e757ed1db508c56821 /llvm/test/Transforms/InstCombine/icmp-add.ll | |
| parent | fe67255961e25c1d88888831d5badb3ec96b4ba2 (diff) | |
| download | bcm5719-llvm-53c5c3d65df3d48fd147b7786ef56cf9da6548d2.tar.gz bcm5719-llvm-53c5c3d65df3d48fd147b7786ef56cf9da6548d2.zip | |
[InstCombine] add nsw/nuw X, signbit --> or X, signbit
Changing to 'or' (rather than 'xor' when no wrapping flags are set)
allows icmp simplifies to happen as expected.
Differential Revision: https://reviews.llvm.org/D29729
llvm-svn: 295574
Diffstat (limited to 'llvm/test/Transforms/InstCombine/icmp-add.ll')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/icmp-add.ll | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/llvm/test/Transforms/InstCombine/icmp-add.ll b/llvm/test/Transforms/InstCombine/icmp-add.ll index 7345621045d..efeb9d5bb45 100644 --- a/llvm/test/Transforms/InstCombine/icmp-add.ll +++ b/llvm/test/Transforms/InstCombine/icmp-add.ll @@ -223,24 +223,22 @@ define i1 @nsw_slt5_ov(i8 %a) { ret i1 %c } -; FIXME: InstCombine should not lose wrapping information by changing the add to xor. +; InstCombine should not thwart this opportunity to simplify completely. define i1 @slt_zero_add_nsw_signbit(i8 %x) { ; CHECK-LABEL: @slt_zero_add_nsw_signbit( -; CHECK-NEXT: [[Z:%.*]] = icmp sgt i8 %x, -1 -; CHECK-NEXT: ret i1 [[Z]] +; CHECK-NEXT: ret i1 true ; %y = add nsw i8 %x, -128 %z = icmp slt i8 %y, 0 ret i1 %z } -; FIXME: InstCombine should not lose wrapping information by changing the add to xor. +; InstCombine should not thwart this opportunity to simplify completely. define i1 @slt_zero_add_nuw_signbit(i8 %x) { ; CHECK-LABEL: @slt_zero_add_nuw_signbit( -; CHECK-NEXT: [[Z:%.*]] = icmp sgt i8 %x, -1 -; CHECK-NEXT: ret i1 [[Z]] +; CHECK-NEXT: ret i1 true ; %y = add nuw i8 %x, 128 %z = icmp slt i8 %y, 0 |
