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InstCombine: Make sure we use the pre-zext type when creating a constant of a value that is zext'd. 

Fixes PR13250.

llvm-svn: 164377
This commit is contained in:
Benjamin Kramer 2012-09-21 16:26:41 +00:00
parent 29ebecb11a
commit efb4d34bcf
2 changed files with 16 additions and 1 deletions
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3
llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
View File

@ -477,7 +477,8 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) ||
match(Op1, m_ZExt(m_Shl(m_Power2(CI), m_Value(N))))) {
if (*CI != 1)
N = Builder->CreateAdd(N, ConstantInt::get(I.getType(),CI->logBase2()));
N = Builder->CreateAdd(N,
ConstantInt::get(N->getType(), CI->logBase2()));
if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
N = Builder->CreateZExt(N, Z->getDestTy());
if (I.isExact())

14
llvm/test/Transforms/InstCombine/div-shift.ll
View File

@ -21,3 +21,17 @@ define i64 @t2(i64 %x, i32 %y) nounwind {
%3 = udiv i64 %x, %2
ret i64 %3
}
; PR13250
define i64 @t3(i64 %x, i32 %y) nounwind {
; CHECK: t3
; CHECK-NOT: udiv
; CHECK-NEXT: %1 = add i32 %y, 2
; CHECK-NEXT: %2 = zext i32 %1 to i64
; CHECK-NEXT: %3 = lshr i64 %x, %2
; CHECK-NEXT: ret i64 %3
%1 = shl i32 4, %y
%2 = zext i32 %1 to i64
%3 = udiv i64 %x, %2
ret i64 %3
}