InstCombine: Preserve nsw when folding X*(2^C) -> X << C

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222606 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Majnemer 2014-11-22 04:52:55 +00:00
parent 156d6ec86b
commit fc1c5babaf
3 changed files with 7 additions and 5 deletions

View File

@ -179,6 +179,8 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
if (I.hasNoUnsignedWrap())
Shl->setHasNoUnsignedWrap();
if (I.hasNoSignedWrap() && NewCst->isNotMinSignedValue())
Shl->setHasNoSignedWrap();
return Shl;
}

View File

@ -219,7 +219,7 @@ define i16 @mul_add_to_mul_1(i16 %x) {
%add2 = add nsw i16 %x, %mul1
ret i16 %add2
; CHECK-LABEL: @mul_add_to_mul_1(
; CHECK-NEXT: %add2 = mul i16 %x, 9
; CHECK-NEXT: %add2 = mul nsw i16 %x, 9
; CHECK-NEXT: ret i16 %add2
}
@ -228,7 +228,7 @@ define i16 @mul_add_to_mul_2(i16 %x) {
%add2 = add nsw i16 %mul1, %x
ret i16 %add2
; CHECK-LABEL: @mul_add_to_mul_2(
; CHECK-NEXT: %add2 = mul i16 %x, 9
; CHECK-NEXT: %add2 = mul nsw i16 %x, 9
; CHECK-NEXT: ret i16 %add2
}
@ -248,7 +248,7 @@ define i16 @mul_add_to_mul_4(i16 %a) {
%add = add nsw i16 %mul1, %mul2
ret i16 %add
; CHECK-LABEL: @mul_add_to_mul_4(
; CHECK-NEXT: %add = mul i16 %a, 9
; CHECK-NEXT: %add = mul nsw i16 %a, 9
; CHECK-NEXT: ret i16 %add
}

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@ -217,7 +217,7 @@ define i32 @test25(i32 %a) {
%div = sdiv i32 %shl, 2
ret i32 %div
; CHECK-LABEL: @test25(
; CHECK-NEXT: %div = shl i32 %a, 1
; CHECK-NEXT: %div = shl nsw i32 %a, 1
; CHECK-NEXT: ret i32 %div
}
@ -226,7 +226,7 @@ define i32 @test26(i32 %a) {
%div = sdiv i32 %mul, 3
ret i32 %div
; CHECK-LABEL: @test26(
; CHECK-NEXT: %div = shl i32 %a, 2
; CHECK-NEXT: %div = shl nsw i32 %a, 2
; CHECK-NEXT: ret i32 %div
}