RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-21 20:12:56 +02:00
Code Issues Projects Releases Wiki Activity

NewGVN: Fix PR32403 - Handling of undef in phis was not quite correct

Browse Source 
due to LLVM's view of phi nodes.  It would cause NewGVN not to fixpoint
in some interesting edge cases.

llvm-svn: 298687
This commit is contained in:
Daniel Berlin 2017-03-24 05:30:34 +00:00
parent b3d605ee1f
commit 9f0bf61efa
2 changed files with 79 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Transforms/Scalar/NewGVN.cpp
View File

@ -368,6 +368,7 @@ private:
const Expression *performSymbolicPredicateInfoEvaluation(Instruction *);
// Congruence finding.
bool someEquivalentDominates(const Instruction *, const Instruction *) const;
Value *lookupOperandLeader(Value *) const;
void performCongruenceFinding(Instruction *, const Expression *);
void moveValueToNewCongruenceClass(Instruction *, CongruenceClass *,
@ -724,6 +725,18 @@ const CallExpression *NewGVN::createCallExpression(CallInst *CI,
return E;
}
// Return true if some equivalent of instruction Inst dominates instruction U.
bool NewGVN::someEquivalentDominates(const Instruction *Inst,
const Instruction *U) const {
auto *CC = ValueToClass.lookup(Inst);
assert(isa<Instruction>(CC->RepLeader) && CC->RepLeader == Inst);
if (CC)
return llvm::any_of(CC->Members, [&](const Value *Member) {
return DT->dominates(cast<Instruction>(Member), U);
});
return false;
}
// See if we have a congruence class and leader for this operand, and if so,
// return it. Otherwise, return the operand itself.
Value *NewGVN::lookupOperandLeader(Value *V) const {
@ -1054,7 +1067,7 @@ const Expression *NewGVN::performSymbolicPHIEvaluation(Instruction *I) {
if (HasUndef) {
// Only have to check for instructions
if (auto *AllSameInst = dyn_cast<Instruction>(AllSameValue))
if (!DT->dominates(AllSameInst, I))
if (!someEquivalentDominates(AllSameInst, I))
return E;
}

65
test/Transforms/NewGVN/pr32403.ll Normal file
View File

@ -0,0 +1,65 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
;RUN: opt -newgvn -S < %s | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.12.0"
; Function Attrs: nounwind ssp uwtable
define void @reorder_ref_pic_list() local_unnamed_addr {
; CHECK-LABEL: @reorder_ref_pic_list(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 undef, label [[FOR_END:%.*]], label [[FOR_BODY_PREHEADER:%.*]]
; CHECK: for.body.preheader:
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[REFIDXLX_0:%.*]] = phi i32 [ [[INC_I51:%.*]], [[IF_ELSE58:%.*]] ], [ 0, [[FOR_BODY_PREHEADER]] ]
; CHECK-NEXT: br i1 undef, label [[IF_THEN13:%.*]], label [[IF_ELSE58]]
; CHECK: if.then13:
; CHECK-NEXT: [[INC_I:%.*]] = add nsw i32 [[REFIDXLX_0]], 1
; CHECK-NEXT: br label [[FOR_BODY8_I:%.*]]
; CHECK: for.body8.i:
; CHECK-NEXT: br i1 undef, label [[FOR_INC24_I:%.*]], label [[IF_THEN17_I:%.*]]
; CHECK: if.then17.i:
; CHECK-NEXT: br label [[FOR_INC24_I]]
; CHECK: for.inc24.i:
; CHECK-NEXT: br label [[FOR_BODY8_I]]
; CHECK: if.else58:
; CHECK-NEXT: [[INC_I51]] = add nsw i32 [[REFIDXLX_0]], 1
; CHECK-NEXT: br label [[FOR_BODY]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
entry:
br i1 undef, label %for.end, label %for.body.preheader
for.body.preheader: ; preds = %entry
br label %for.body
for.body: ; preds = %if.else58, %for.body.preheader
%refIdxLX.0 = phi i32 [ %inc.i51, %if.else58 ], [ 0, %for.body.preheader ]
br i1 undef, label %if.then13, label %if.else58
if.then13: ; preds = %for.body
%inc.i = add nsw i32 %refIdxLX.0, 1
br label %for.body8.i
for.body8.i: ; preds = %for.inc24.i, %if.then13
%nIdx.052.i = phi i32 [ %inc.i, %if.then13 ], [ %nIdx.1.i, %for.inc24.i ]
br i1 undef, label %for.inc24.i, label %if.then17.i
if.then17.i: ; preds = %for.body8.i
br label %for.inc24.i
for.inc24.i: ; preds = %if.then17.i, %for.body8.i
%nIdx.1.i = phi i32 [ undef, %if.then17.i ], [ %nIdx.052.i, %for.body8.i ]
br label %for.body8.i
if.else58: ; preds = %for.body
%inc.i51 = add nsw i32 %refIdxLX.0, 1
br label %for.body
for.end: ; preds = %entry
ret void
}