RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-12-05 10:17:36 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fixes PR2395. Looking for a constant in a GEP tail (when the first GEP

Browse Source 
is longer than the second one) should stop after finding one. Added break 
instruction guarantees it. It also changes difference between offsets to 
absolute value of this difference in the condition.

llvm-svn: 51875
This commit is contained in:
Wojciech Matyjewicz 2008-06-02 17:26:12 +00:00
parent e79dd8c21a
commit 06e4c8a420
2 changed files with 22 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
lib/Analysis/BasicAliasAnalysis.cpp
View File

@ -687,7 +687,7 @@ BasicAliasAnalysis::CheckGEPInstructions(
if (isa<ConstantInt>(GEP1Ops[i]) &&
!cast<ConstantInt>(GEP1Ops[i])->isZero()) {
// Yup, there's a constant in the tail. Set all variables to
// constants in the GEP instruction to make it suiteable for
// constants in the GEP instruction to make it suitable for
// TargetData::getIndexedOffset.
for (i = 0; i != MaxOperands; ++i)
if (!isa<ConstantInt>(GEP1Ops[i]))
@ -702,9 +702,15 @@ BasicAliasAnalysis::CheckGEPInstructions(
int64_t Offset2 = TD.getIndexedOffset(GEPPointerTy, GEP1Ops,
MinOperands);
// Make sure we compare the absolute difference.
if (Offset1 > Offset2)
std::swap(Offset1, Offset2);
// If the tail provided a bit enough offset, return noalias!
if ((uint64_t)(Offset2-Offset1) >= SizeMax)
return NoAlias;
// Otherwise break - we don't look for another constant in the tail.
break;
}
}

15
test/Analysis/BasicAA/2008-06-02-GEPTailCrash.ll Normal file
View File

@ -0,0 +1,15 @@
; RUN: llvm-as < %s | opt -gvn -disable-output
; PR2395
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
target triple = "i686-pc-linux-gnu"
%struct.S291 = type <{ %union.anon, i32 }>
%union.anon = type { }
@a291 = external global [5 x %struct.S291] ; <[5 x %struct.S291]*> [#uses=2]
define void @test291() nounwind {
entry:
store i32 1138410269, i32* getelementptr ([5 x %struct.S291]* @a291, i32 0, i32 2, i32 1)
%tmp54 = load i32* bitcast (%struct.S291* getelementptr ([5 x %struct.S291]* @a291, i32 0, i32 2) to i32*), align 4 ; <i32> [#uses=0]
unreachable
}