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Fix the folding of multiplication into addresses on x86, which was broken

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by the recent {U,S}MUL_LOHI changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43230 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2007-10-22 20:22:24 +00:00
parent 3311876c3c
commit 8368805e25
2 changed files with 35 additions and 0 deletions
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5
lib/Target/X86/X86ISelDAGToDAG.cpp
View File

@ -681,6 +681,11 @@ bool X86DAGToDAGISel::MatchAddress(SDOperand N, X86ISelAddressMode &AM,
}
break;
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI:
// A mul_lohi where we need the low part can be folded as a plain multiply.
if (N.ResNo != 0) break;
// FALL THROUGH
case ISD::MUL:
// X*[3,5,9] -> X+X*[2,4,8]
if (!Available &&

30
test/CodeGen/X86/fold-mul-lohi.ll Normal file
View File

@ -0,0 +1,30 @@
; RUN: llvm-as < %s | llc -march=x86 | not grep lea
; RUN: llvm-as < %s | llc -march=x86-64 | not grep lea
@B = external global [1000 x i8], align 32
@A = external global [1000 x i8], align 32
@P = external global [1000 x i8], align 32
define void @foo(i32 %m) {
entry:
%tmp1 = icmp sgt i32 %m, 0
br i1 %tmp1, label %bb, label %return
bb:
%i.019.0 = phi i32 [ %indvar.next, %bb ], [ 0, %entry ]
%tmp2 = getelementptr [1000 x i8]* @B, i32 0, i32 %i.019.0
%tmp3 = load i8* %tmp2, align 4
%tmp4 = mul i8 %tmp3, 2
%tmp5 = getelementptr [1000 x i8]* @A, i32 0, i32 %i.019.0
store i8 %tmp4, i8* %tmp5, align 4
%tmp8 = mul i32 %i.019.0, 9
%tmp10 = getelementptr [1000 x i8]* @P, i32 0, i32 %tmp8
store i8 17, i8* %tmp10, align 4
%indvar.next = add i32 %i.019.0, 1
%exitcond = icmp eq i32 %indvar.next, %m
br i1 %exitcond, label %return, label %bb
return:
ret void
}