[llvm] r323079 - Revert [SCEV] Fix isLoopEntryGuardedByCond usage
Serguei Katkov via llvm-commits
llvm-commits at lists.llvm.org
Sun Jan 21 23:47:02 PST 2018
Author: skatkov
Date: Sun Jan 21 23:47:02 2018
New Revision: 323079
URL: http://llvm.org/viewvc/llvm-project?rev=323079&view=rev
Log:
Revert [SCEV] Fix isLoopEntryGuardedByCond usage
It causes buildbot failures. New added assert is fired.
It seems not all usages of isLoopEntryGuardedByCond are fixed.
Removed:
llvm/trunk/test/Transforms/IndVarSimplify/inner-loop.ll
Modified:
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=323079&r1=323078&r2=323079&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Sun Jan 21 23:47:02 2018
@@ -8669,8 +8669,7 @@ bool ScalarEvolution::isKnownPredicate(I
bool RightGuarded = false;
if (LAR) {
const Loop *L = LAR->getLoop();
- if (isAvailableAtLoopEntry(RHS, L) &&
- isLoopEntryGuardedByCond(L, Pred, LAR->getStart(), RHS) &&
+ if (isLoopEntryGuardedByCond(L, Pred, LAR->getStart(), RHS) &&
isLoopBackedgeGuardedByCond(L, Pred, LAR->getPostIncExpr(*this), RHS)) {
if (!RAR) return true;
LeftGuarded = true;
@@ -8678,8 +8677,7 @@ bool ScalarEvolution::isKnownPredicate(I
}
if (RAR) {
const Loop *L = RAR->getLoop();
- if (isAvailableAtLoopEntry(LHS, L) &&
- isLoopEntryGuardedByCond(L, Pred, LHS, RAR->getStart()) &&
+ if (isLoopEntryGuardedByCond(L, Pred, LHS, RAR->getStart()) &&
isLoopBackedgeGuardedByCond(L, Pred, LHS, RAR->getPostIncExpr(*this))) {
if (!LAR) return true;
RightGuarded = true;
@@ -9060,12 +9058,6 @@ bool
ScalarEvolution::isLoopEntryGuardedByCond(const Loop *L,
ICmpInst::Predicate Pred,
const SCEV *LHS, const SCEV *RHS) {
- // Both LHS and RHS must be available at loop entry.
- assert(isAvailableAtLoopEntry(LHS, L) &&
- "LHS is not available at Loop Entry");
- assert(isAvailableAtLoopEntry(RHS, L) &&
- "RHS is not available at Loop Entry");
-
// Interpret a null as meaning no loop, where there is obviously no guard
// (interprocedural conditions notwithstanding).
if (!L) return false;
Modified: llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp?rev=323079&r1=323078&r2=323079&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp Sun Jan 21 23:47:02 2018
@@ -934,9 +934,9 @@ LoopStructure::parseLoopStructure(Scalar
return None;
}
- if (!SE.isAvailableAtLoopEntry(RightSCEV, &L) ||
- !SE.isLoopEntryGuardedByCond(&L, BoundPred, IndVarStart,
- SE.getAddExpr(RightSCEV, Step))) {
+ if (!SE.isLoopEntryGuardedByCond(
+ &L, BoundPred, IndVarStart,
+ SE.getAddExpr(RightSCEV, Step))) {
FailureReason = "Induction variable start not bounded by upper limit";
return None;
}
@@ -948,8 +948,7 @@ LoopStructure::parseLoopStructure(Scalar
RightValue = B.CreateAdd(RightValue, One);
}
} else {
- if (!SE.isAvailableAtLoopEntry(RightSCEV, &L) ||
- !SE.isLoopEntryGuardedByCond(&L, BoundPred, IndVarStart, RightSCEV)) {
+ if (!SE.isLoopEntryGuardedByCond(&L, BoundPred, IndVarStart, RightSCEV)) {
FailureReason = "Induction variable start not bounded by upper limit";
return None;
}
@@ -1015,10 +1014,9 @@ LoopStructure::parseLoopStructure(Scalar
return None;
}
- if (!SE.isAvailableAtLoopEntry(RightSCEV, &L) ||
- !SE.isLoopEntryGuardedByCond(
- &L, BoundPred, IndVarStart,
- SE.getMinusSCEV(RightSCEV, SE.getOne(RightSCEV->getType())))) {
+ if (!SE.isLoopEntryGuardedByCond(
+ &L, BoundPred, IndVarStart,
+ SE.getMinusSCEV(RightSCEV, SE.getOne(RightSCEV->getType())))) {
FailureReason = "Induction variable start not bounded by lower limit";
return None;
}
@@ -1030,8 +1028,7 @@ LoopStructure::parseLoopStructure(Scalar
RightValue = B.CreateSub(RightValue, One);
}
} else {
- if (!SE.isAvailableAtLoopEntry(RightSCEV, &L) ||
- !SE.isLoopEntryGuardedByCond(&L, BoundPred, IndVarStart, RightSCEV)) {
+ if (!SE.isLoopEntryGuardedByCond(&L, BoundPred, IndVarStart, RightSCEV)) {
FailureReason = "Induction variable start not bounded by lower limit";
return None;
}
Removed: llvm/trunk/test/Transforms/IndVarSimplify/inner-loop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/inner-loop.ll?rev=323078&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/inner-loop.ll (original)
+++ llvm/trunk/test/Transforms/IndVarSimplify/inner-loop.ll (removed)
@@ -1,54 +0,0 @@
-; RUN: opt < %s -indvars -S | FileCheck %s
-
-; This is regression test for the bug in ScalarEvolution::isKnownPredicate.
-; It does not check whether SCEV is available at loop entry before invoking
-; and utility function isLoopEntryGuardedByCond and that leads to miscompile.
-
-target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:1"
-target triple = "x86_64-unknown-linux-gnu"
-
-declare void @foo(i64)
-declare void @bar(i32)
-
-define void @test(i8* %arr) {
-entry:
- br label %outer_header
-
-outer_header:
- %i = phi i32 [40, %entry], [%i.next, %outer_latch]
- %i.64 = sext i32 %i to i64
- br label %inner_header
-
-inner_header:
- %j = phi i32 [27, %outer_header], [%j.next, %inner_backedge]
- %j1 = zext i32 %j to i64
-; The next 4 lines are required for avoid widening of %j and
-; SCEV at %cmp would not be AddRec.
- %gep = getelementptr inbounds i8, i8* %arr, i64 %j1
- %ld = load i8, i8* %gep
- %ec = icmp eq i8 %ld, 0
- br i1 %ec, label %return, label %inner_backedge
-
-inner_backedge:
- %cmp = icmp ult i32 %j, %i
- %s = select i1 %cmp, i32 %i, i32 %j
-; Select should not be simplified because if
-; %i == 26 and %j == 27, %s should be equal to %j.
-; In case of a bug the instruction is simplified to
-; %s = select i1 true, i32 %0, i32 %j
-; CHECK-NOT: %s = select i1 true
- call void @bar(i32 %s)
- %j.next = add nsw i32 %j, -2
- %cond = icmp ult i32 %j, 3
- br i1 %cond, label %outer_latch, label %inner_header
-
-outer_latch:
- %i.next = add i32 %i, -1
- %cond2 = icmp sgt i32 %i.next, 13
-; This line is just for forcing widening of %i
- call void @foo(i64 %i.64)
- br i1 %cond2, label %outer_header, label %return
-
-return:
- ret void
-}
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