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c531da60aa
1. Only perform (zext (shl (zext x), y)) -> (shl (zext x), y) when y is a constant. This makes sure it remove at least one zest. 2. If the shift is a left shift, make sure the original shift cannot shift out bits. llvm-svn: 91399
26 lines
461 B
LLVM
26 lines
461 B
LLVM
; RUN: llc < %s -march=x86 | FileCheck %s
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define i32 @t1(i8 zeroext %x) nounwind readnone ssp {
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entry:
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; CHECK: t1:
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; CHECK: shll
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; CHECK-NOT: movzwl
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; CHECK: ret
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%0 = zext i8 %x to i16
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%1 = shl i16 %0, 5
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%2 = zext i16 %1 to i32
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ret i32 %2
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}
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define i32 @t2(i8 zeroext %x) nounwind readnone ssp {
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entry:
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; CHECK: t2:
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; CHECK: shrl
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; CHECK-NOT: movzwl
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; CHECK: ret
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%0 = zext i8 %x to i16
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%1 = lshr i16 %0, 3
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%2 = zext i16 %1 to i32
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ret i32 %2
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}
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