From 53c86db25b5b4e163c68dc91c8ce1bc8180e6ff3 Mon Sep 17 00:00:00 2001
From: Hal Finkel <hfinkel@anl.gov>
Date: Thu, 11 Jul 2013 16:31:51 +0000
Subject: PPCDAGToDAGISel::isRunOfOnes should return false on zero
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
---
lib/Target/PowerPC/PPCISelDAGToDAG.cpp | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
(limited to 'lib')
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 901d369..475bde1 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -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) &&
--
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