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PPCDAGToDAGISel::isRunOfOnes should return false on zero

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This fixes a bug (found by csmith) at -O0 where we attempt to create a RLWIMI
with an out-of-range operand. Most uses of the isRunOfOnes function are guarded
by a condition that the value is not zero. This was not true in two places, and
in both places a zero input would result in an out-of-rage MB value (= 32).

To fix this, isRunOfOnes returns false on a zero input (and I've remove one
now-redundant guard).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186101 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-07-11 16:31:51 +00:00
parent 9e639e8fd9
commit 53c86db25b
2 changed files with 31 additions and 1 deletions
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5
lib/Target/PowerPC/PPCISelDAGToDAG.cpp
View File

@ -330,6 +330,9 @@ static bool isOpcWithIntImmediate(SDNode *N, unsigned Opc, unsigned& Imm) {
}
bool PPCDAGToDAGISel::isRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME) {
if (!Val)
return false;
if (isShiftedMask_32(Val)) {
// look for the first non-zero bit
MB = countLeadingZeros(Val);
@ -435,7 +438,7 @@ SDNode *PPCDAGToDAGISel::SelectBitfieldInsert(SDNode *N) {
}
unsigned MB, ME;
if (InsertMask && isRunOfOnes(InsertMask, MB, ME)) {
if (isRunOfOnes(InsertMask, MB, ME)) {
SDValue Tmp1, Tmp2;
if ((Op1Opc == ISD::SHL || Op1Opc == ISD::SRL) &&

27
test/CodeGen/PowerPC/zero-not-run.ll Normal file
View File

@ -0,0 +1,27 @@
; RUN: llc -O0 -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 < %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-unknown-linux-gnu"
; Function Attrs: nounwind
define internal i32* @func_65(i32* %p_66) #0 {
entry:
br i1 undef, label %for.body, label %for.end731
for.body: ; preds = %entry
%0 = load i32* undef, align 4
%or31 = or i32 %0, 319143828
store i32 %or31, i32* undef, align 4
%cmp32 = icmp eq i32 319143828, %or31
%conv33 = zext i1 %cmp32 to i32
%conv34 = sext i32 %conv33 to i64
%call35 = call i64 @safe_mod_func_uint64_t_u_u(i64 %conv34, i64 -10)
unreachable
for.end731: ; preds = %entry
ret i32* undef
}
; Function Attrs: nounwind
declare i64 @safe_mod_func_uint64_t_u_u(i64, i64) #0
attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }