6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-07-21 02:29:22 +00:00
Code Issues Projects Releases Wiki Activity

fix PR9013, an infinite loop in instcombine.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123968 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2011-01-21 05:29:50 +00:00
parent 084fe6243a
commit cd151d2f95
2 changed files with 27 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
lib/Transforms/InstCombine/InstructionCombining.cpp
View File

@ -538,9 +538,11 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
if (!PN->hasOneUse()) {
// Walk the use list for the instruction, comparing them to I.
for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
UI != E; ++UI)
if (!I.isIdenticalTo(cast<Instruction>(*UI)))
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
if (User != &I && !I.isIdenticalTo(User))
return 0;
}
// Otherwise, we can replace *all* users with the new PHI we form.
}
@ -565,6 +567,12 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
if (InvokeInst *II = dyn_cast<InvokeInst>(InVal))
if (II->getParent() == NonConstBB)
return 0;
// If the incoming non-constant value is in I's block, we will remove one
// instruction, but insert another equivalent one, leading to infinite
// instcombine.
if (NonConstBB == I.getParent())
return 0;
}
// If there is exactly one non-constant value, we can insert a copy of the

17
test/Transforms/InstCombine/crash.ll
View File

@ -353,3 +353,20 @@ entry:
ret %struct.basic_ios* %0
}
; PR9013
define void @test18() nounwind ssp {
entry:
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%l_197.0 = phi i32 [ 0, %entry ], [ %sub.i, %for.inc ]
br label %for.inc
for.inc: ; preds = %for.cond
%conv = and i32 %l_197.0, 255
%sub.i = add nsw i32 %conv, -1
br label %for.cond
return: ; No predecessors!
ret void
}