mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-22 10:29:35 +00:00
Just mark the sign bit as known zero, rather than any other irrelevant bits
known zero in the LHS. Fixes PR12541. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155818 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
bfbab99b58
commit
5ff30e70f8
@ -564,7 +564,7 @@ void llvm::ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne,
|
||||
Depth+1);
|
||||
// If it's known zero, our sign bit is also zero.
|
||||
if (LHSKnownZero.isNegative())
|
||||
KnownZero |= LHSKnownZero;
|
||||
KnownZero.setBit(BitWidth - 1);
|
||||
}
|
||||
|
||||
break;
|
||||
|
12
test/Transforms/InstCombine/2012-04-30-SRem.ll
Normal file
12
test/Transforms/InstCombine/2012-04-30-SRem.ll
Normal file
@ -0,0 +1,12 @@
|
||||
; RUN: opt -instcombine -S < %s | FileCheck %s
|
||||
; PR12541
|
||||
|
||||
define i32 @foo(i32 %x) {
|
||||
%y = xor i32 %x, 3
|
||||
%z = srem i32 1656690544, %y
|
||||
%sext = shl i32 %z, 24
|
||||
%s = ashr exact i32 %sext, 24
|
||||
ret i32 %s
|
||||
; CHECK-NOT: and
|
||||
; The shifts were wrongly being turned into an and with 112
|
||||
}
|
Loading…
Reference in New Issue
Block a user