[llvm] r358192 - [ConstantFold] ExtractConstantBytes - handle shifts on large integer types
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 11 09:39:31 PDT 2019
Author: rksimon
Date: Thu Apr 11 09:39:31 2019
New Revision: 358192
URL: http://llvm.org/viewvc/llvm-project?rev=358192&view=rev
Log:
[ConstantFold] ExtractConstantBytes - handle shifts on large integer types
Use APInt instead of getZExtValue from the ConstantInt until we can confirm that the shift amount is in range.
Reduced from OSS-Fuzz #14169 - https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=14169
Added:
llvm/trunk/test/Transforms/InstCombine/constant-fold-shifts.ll
Modified:
llvm/trunk/lib/IR/ConstantFold.cpp
Modified: llvm/trunk/lib/IR/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=358192&r1=358191&r2=358192&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp (original)
+++ llvm/trunk/lib/IR/ConstantFold.cpp Thu Apr 11 09:39:31 2019
@@ -268,19 +268,20 @@ static Constant *ExtractConstantBytes(Co
ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
if (!Amt)
return nullptr;
- unsigned ShAmt = Amt->getZExtValue();
+ APInt ShAmt = Amt->getValue();
// Cannot analyze non-byte shifts.
if ((ShAmt & 7) != 0)
return nullptr;
- ShAmt >>= 3;
+ ShAmt.lshrInPlace(3);
// If the extract is known to be all zeros, return zero.
- if (ByteStart >= CSize-ShAmt)
- return Constant::getNullValue(IntegerType::get(CE->getContext(),
- ByteSize*8));
+ if (ShAmt.uge(CSize - ByteStart))
+ return Constant::getNullValue(
+ IntegerType::get(CE->getContext(), ByteSize * 8));
// If the extract is known to be fully in the input, extract it.
- if (ByteStart+ByteSize+ShAmt <= CSize)
- return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
+ if (ShAmt.ule(CSize - (ByteStart + ByteSize)))
+ return ExtractConstantBytes(CE->getOperand(0),
+ ByteStart + ShAmt.getZExtValue(), ByteSize);
// TODO: Handle the 'partially zero' case.
return nullptr;
@@ -290,19 +291,20 @@ static Constant *ExtractConstantBytes(Co
ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
if (!Amt)
return nullptr;
- unsigned ShAmt = Amt->getZExtValue();
+ APInt ShAmt = Amt->getValue();
// Cannot analyze non-byte shifts.
if ((ShAmt & 7) != 0)
return nullptr;
- ShAmt >>= 3;
+ ShAmt.lshrInPlace(3);
// If the extract is known to be all zeros, return zero.
- if (ByteStart+ByteSize <= ShAmt)
- return Constant::getNullValue(IntegerType::get(CE->getContext(),
- ByteSize*8));
+ if (ShAmt.uge(ByteStart + ByteSize))
+ return Constant::getNullValue(
+ IntegerType::get(CE->getContext(), ByteSize * 8));
// If the extract is known to be fully in the input, extract it.
- if (ByteStart >= ShAmt)
- return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
+ if (ShAmt.ule(ByteStart))
+ return ExtractConstantBytes(CE->getOperand(0),
+ ByteStart - ShAmt.getZExtValue(), ByteSize);
// TODO: Handle the 'partially zero' case.
return nullptr;
Added: llvm/trunk/test/Transforms/InstCombine/constant-fold-shifts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/constant-fold-shifts.ll?rev=358192&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/constant-fold-shifts.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/constant-fold-shifts.ll Thu Apr 11 09:39:31 2019
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+ at A = external constant i32
+
+; OSS-Fuzz #14169
+; https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=14169
+define void @ossfuzz_14169_test1(i32* %a0) {
+; CHECK-LABEL: @ossfuzz_14169_test1(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: ret void
+;
+bb:
+ %B = ptrtoint i32* @A to i64
+ %C = icmp sge i64 %B, 0
+ %X = select i1 %C, i712 0, i712 1
+ %B9 = lshr i712 %X, 146783911423364576743092537299333564210980159306769991919205685720763064069663027716481187399048043939495936
+ %G5 = getelementptr i64, i64* undef, i712 %B9
+ store i64* %G5, i64** undef
+ ret void
+}
+
+define void @ossfuzz_14169_test2(i32* %a0) {
+; CHECK-LABEL: @ossfuzz_14169_test2(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: ret void
+;
+bb:
+ %B = ptrtoint i32* @A to i64
+ %C = icmp sge i64 %B, 0
+ %X = select i1 %C, i712 0, i712 1
+ %B9 = shl i712 %X, 146783911423364576743092537299333564210980159306769991919205685720763064069663027716481187399048043939495936
+ %G5 = getelementptr i64, i64* undef, i712 %B9
+ store i64* %G5, i64** undef
+ ret void
+}
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