Fix a PPC rlwimi instruction-selection bug

Under certain (evidently rare) circumstances, this code used to convert OR(a,
AND(x, y)) into OR(a, x). This was incorrect.

While there, I've added a comment to the code immediately above.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185201 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-06-28 20:00:07 +00:00
parent 3ca4fa7c26
commit 2c77a625b7
2 changed files with 46 additions and 2 deletions

View File

@ -447,10 +447,10 @@ SDNode *PPCDAGToDAGISel::SelectBitfieldInsert(SDNode *N) {
unsigned SHOpc = Op1.getOperand(0).getOpcode();
if ((SHOpc == ISD::SHL || SHOpc == ISD::SRL) &&
isInt32Immediate(Op1.getOperand(0).getOperand(1), Value)) {
// Note that Value must be in range here (less than 32) because
// otherwise there would not be any bits set in InsertMask.
Op1 = Op1.getOperand(0).getOperand(0);
SH = (SHOpc == ISD::SHL) ? Value : 32 - Value;
} else {
Op1 = Op1.getOperand(0);
}
}

View File

@ -0,0 +1,44 @@
; RUN: llc -mcpu=pwr7 < %s | FileCheck %s
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-bgq-linux"
define void @test() align 2 {
entry:
br i1 undef, label %codeRepl1, label %codeRepl31
codeRepl1: ; preds = %entry
br i1 undef, label %codeRepl4, label %codeRepl29
codeRepl4: ; preds = %codeRepl1
br i1 undef, label %codeRepl12, label %codeRepl17
codeRepl12: ; preds = %codeRepl4
unreachable
codeRepl17: ; preds = %codeRepl4
%0 = load i8* undef, align 2
%1 = and i8 %0, 1
%not.tobool.i.i.i = icmp eq i8 %1, 0
%2 = select i1 %not.tobool.i.i.i, i16 0, i16 256
%3 = load i8* undef, align 1
%4 = and i8 %3, 1
%not.tobool.i.1.i.i = icmp eq i8 %4, 0
%rvml38.sroa.1.1.insert.ext = select i1 %not.tobool.i.1.i.i, i16 0, i16 1
%rvml38.sroa.0.0.insert.insert = or i16 %rvml38.sroa.1.1.insert.ext, %2
store i16 %rvml38.sroa.0.0.insert.insert, i16* undef, align 2
unreachable
; CHECK: @test
; CHECK-DAG: slwi [[R1:[0-9]+]],
; CHECK-DAG: rlwinm [[R2:[0-9]+]],
; CHECK-DAG: srawi [[R3:[0-9]+]], [[R1]]
; CHECK-DAG: rlwinm [[R4:[0-9]+]], [[R3]], 0, 23, 23
; CHECK: rlwimi [[R4]], [[R2]], 0,
codeRepl29: ; preds = %codeRepl1
unreachable
codeRepl31: ; preds = %entry
ret void
}