diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/and.ll | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/and.ll b/llvm/test/Transforms/InstCombine/and.ll index c12662d4db0..f5ee4022ce8 100644 --- a/llvm/test/Transforms/InstCombine/and.ll +++ b/llvm/test/Transforms/InstCombine/and.ll @@ -368,6 +368,25 @@ define <2 x i32> @and_demanded_bits_splat_vec(<2 x i32> %x) { ret <2 x i32> %z } +; zext (x >> 8) has all zeros in the high 24-bits: 0x000000xx +; (y | 255) has all ones in the low 8-bits: 0xyyyyyyff +; 'and' of those is all known bits - it's just 'z'. + +define i32 @and_zext_demanded(i16 %x, i32 %y) { +; CHECK-LABEL: @and_zext_demanded( +; CHECK-NEXT: [[S:%.*]] = lshr i16 %x, 8 +; CHECK-NEXT: [[Z:%.*]] = zext i16 [[S]] to i32 +; CHECK-NEXT: [[O:%.*]] = or i32 %y, 255 +; CHECK-NEXT: [[A:%.*]] = and i32 [[O]], [[Z]] +; CHECK-NEXT: ret i32 [[A]] +; + %s = lshr i16 %x, 8 + %z = zext i16 %s to i32 + %o = or i32 %y, 255 + %a = and i32 %o, %z + ret i32 %a +} + define i32 @test32(i32 %In) { ; CHECK-LABEL: @test32( ; CHECK-NEXT: ret i32 0 |
