RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-02-01 05:01:59 +01:00
Code Issues Projects Releases Wiki Activity

[InstCombine] Check for out of range ashr values using APInt before calling getZExtValue

Browse Source 
Reduced from oss-fuzz #5032 test case

llvm-svn: 322078
This commit is contained in:
Simon Pilgrim 2018-01-09 14:23:46 +00:00
parent 15d7cd9c7a
commit c39efb317d
2 changed files with 28 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
lib/Transforms/InstCombine/InstCombineShifts.cpp
View File

@ -818,7 +818,7 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
Type *Ty = I.getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
const APInt *ShAmtAPInt;
if (match(Op1, m_APInt(ShAmtAPInt))) {
if (match(Op1, m_APInt(ShAmtAPInt)) && ShAmtAPInt->ult(BitWidth)) {
unsigned ShAmt = ShAmtAPInt->getZExtValue();
// If the shift amount equals the difference in width of the destination
@ -832,7 +832,8 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
// We can't handle (X << C1) >>s C2. It shifts arbitrary bits in. However,
// we can handle (X <<nsw C1) >>s C2 since it only shifts in sign bits.
const APInt *ShOp1;
if (match(Op0, m_NSWShl(m_Value(X), m_APInt(ShOp1)))) {
if (match(Op0, m_NSWShl(m_Value(X), m_APInt(ShOp1))) &&
ShOp1->ult(BitWidth)) {
unsigned ShlAmt = ShOp1->getZExtValue();
if (ShlAmt < ShAmt) {
// (X <<nsw C1) >>s C2 --> X >>s (C2 - C1)
@ -850,7 +851,8 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
}
}
if (match(Op0, m_AShr(m_Value(X), m_APInt(ShOp1)))) {
if (match(Op0, m_AShr(m_Value(X), m_APInt(ShOp1))) &&
ShOp1->ult(BitWidth)) {
unsigned AmtSum = ShAmt + ShOp1->getZExtValue();
// Oversized arithmetic shifts replicate the sign bit.
AmtSum = std::min(AmtSum, BitWidth - 1);

23
test/Transforms/InstCombine/shift.ll
View File

@ -1613,3 +1613,26 @@ define i177 @lshr_out_of_range(i177 %Y, i177** %A2) {
%B1 = udiv i177 %B10, %B6
ret i177 %B1
}
; OSS Fuzz #5032
; https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5032
define void @ashr_out_of_range(i177* %A) {
; CHECK-LABEL: @ashr_out_of_range(
; CHECK-NEXT: ret void
;
%L = load i177, i177* %A
%B5 = udiv i177 %L, -1
%B4 = add i177 %B5, -1
%B2 = add i177 %B4, -1
%G11 = getelementptr i177, i177* %A, i177 %B2
%L7 = load i177, i177* %G11
%B6 = mul i177 %B5, %B2
%B24 = ashr i177 %L7, %B6
%B36 = and i177 %L7, %B4
%C17 = icmp sgt i177 %B36, %B24
%G62 = getelementptr i177, i177* %G11, i1 %C17
%B28 = urem i177 %B24, %B6
store i177 %B28, i177* %G62
ret void
}