[llvm] r360260 - Revert "[ValueTracking] Improve isKnowNonZero for Ints"
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Wed May 8 07:50:01 PDT 2019
Author: nikic
Date: Wed May 8 07:50:01 2019
New Revision: 360260
URL: http://llvm.org/viewvc/llvm-project?rev=360260&view=rev
Log:
Revert "[ValueTracking] Improve isKnowNonZero for Ints"
This reverts commit 3b137a495686bd6018d115ea82fb8bb7718349fd.
As reported in https://reviews.llvm.org/D60846, this is causing
miscompiles.
Modified:
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/test/Transforms/InstCombine/known-non-zero.ll
llvm/trunk/test/Transforms/InstSimplify/known-non-zero.ll
llvm/trunk/test/Transforms/LICM/hoist-mustexec.ll
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=360260&r1=360259&r2=360260&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Wed May 8 07:50:01 2019
@@ -1893,9 +1893,10 @@ static bool isGEPKnownNonNull(const GEPO
return false;
}
-static bool isKnownNonZeroFromDominatingCondition(const Value *V,
+static bool isKnownNonNullFromDominatingCondition(const Value *V,
const Instruction *CtxI,
const DominatorTree *DT) {
+ assert(V->getType()->isPointerTy() && "V must be pointer type");
assert(!isa<ConstantData>(V) && "Did not expect ConstantPointerNull");
if (!CtxI || !DT)
@@ -1908,15 +1909,14 @@ static bool isKnownNonZeroFromDominating
break;
NumUsesExplored++;
- // If the value is a pointer and used as an argument to a call or invoke,
- // then argument attributes may provide an answer about null-ness.
- if (V->getType()->isPointerTy())
- if (auto CS = ImmutableCallSite(U))
- if (auto *CalledFunc = CS.getCalledFunction())
- for (const Argument &Arg : CalledFunc->args())
- if (CS.getArgOperand(Arg.getArgNo()) == V &&
- Arg.hasNonNullAttr() && DT->dominates(CS.getInstruction(), CtxI))
- return true;
+ // If the value is used as an argument to a call or invoke, then argument
+ // attributes may provide an answer about null-ness.
+ if (auto CS = ImmutableCallSite(U))
+ if (auto *CalledFunc = CS.getCalledFunction())
+ for (const Argument &Arg : CalledFunc->args())
+ if (CS.getArgOperand(Arg.getArgNo()) == V &&
+ Arg.hasNonNullAttr() && DT->dominates(CS.getInstruction(), CtxI))
+ return true;
// Consider only compare instructions uniquely controlling a branch
CmpInst::Predicate Pred;
@@ -2064,11 +2064,11 @@ bool isKnownNonZero(const Value *V, unsi
}
- if (isKnownNonZeroFromDominatingCondition(V, Q.CxtI, Q.DT))
- return true;
-
// Check for recursive pointer simplifications.
if (V->getType()->isPointerTy()) {
+ if (isKnownNonNullFromDominatingCondition(V, Q.CxtI, Q.DT))
+ return true;
+
// Look through bitcast operations, GEPs, and int2ptr instructions as they
// do not alter the value, or at least not the nullness property of the
// value, e.g., int2ptr is allowed to zero/sign extend the value.
Modified: llvm/trunk/test/Transforms/InstCombine/known-non-zero.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/known-non-zero.ll?rev=360260&r1=360259&r2=360260&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/known-non-zero.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/known-non-zero.ll Wed May 8 07:50:01 2019
@@ -13,7 +13,7 @@ define i32 @test0(i64 %x) {
; CHECK-NEXT: [[C:%.*]] = icmp eq i64 [[X:%.*]], 0
; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
; CHECK: non_zero:
-; CHECK-NEXT: [[CTZ:%.*]] = call i64 @llvm.cttz.i64(i64 [[X]], i1 true), !range !0
+; CHECK-NEXT: [[CTZ:%.*]] = call i64 @llvm.cttz.i64(i64 [[X]], i1 false), !range !0
; CHECK-NEXT: [[CTZ32:%.*]] = trunc i64 [[CTZ]] to i32
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
@@ -40,7 +40,7 @@ define i32 @test1(i64 %x) {
; CHECK-NEXT: [[C:%.*]] = icmp eq i64 [[X:%.*]], 0
; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
; CHECK: non_zero:
-; CHECK-NEXT: [[CTZ:%.*]] = call i64 @llvm.ctlz.i64(i64 [[X]], i1 true), !range !0
+; CHECK-NEXT: [[CTZ:%.*]] = call i64 @llvm.ctlz.i64(i64 [[X]], i1 false), !range !0
; CHECK-NEXT: [[CTZ32:%.*]] = trunc i64 [[CTZ]] to i32
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
Modified: llvm/trunk/test/Transforms/InstSimplify/known-non-zero.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/known-non-zero.ll?rev=360260&r1=360259&r2=360260&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/known-non-zero.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/known-non-zero.ll Wed May 8 07:50:01 2019
@@ -7,7 +7,8 @@ define i64 @test0(i64 %x) {
; CHECK-NEXT: [[A:%.*]] = icmp eq i64 [[X:%.*]], 0
; CHECK-NEXT: br i1 [[A]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
; CHECK: non_zero:
-; CHECK-NEXT: br i1 false, label [[UNREACHABLE:%.*]], label [[EXIT]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i64 [[X]], 0
+; CHECK-NEXT: br i1 [[B]], label [[UNREACHABLE:%.*]], label [[EXIT]]
; CHECK: unreachable:
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
@@ -36,7 +37,8 @@ define i64 @test1(i64 %x) {
; CHECK-NEXT: [[A:%.*]] = icmp eq i64 [[X:%.*]], 0
; CHECK-NEXT: br i1 [[A]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
; CHECK: non_zero:
-; CHECK-NEXT: br i1 true, label [[EXIT]], label [[UNREACHABLE:%.*]]
+; CHECK-NEXT: [[B:%.*]] = icmp ugt i64 [[X]], 0
+; CHECK-NEXT: br i1 [[B]], label [[EXIT]], label [[UNREACHABLE:%.*]]
; CHECK: unreachable:
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
@@ -71,9 +73,11 @@ define i1 @test2(i64 %x, i1 %y) {
; CHECK: two:
; CHECK-NEXT: br label [[MAINBLOCK]]
; CHECK: mainblock:
+; CHECK-NEXT: [[P:%.*]] = phi i64 [ [[X]], [[ONE]] ], [ 42, [[TWO]] ]
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[P]], 0
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
-; CHECK-NEXT: [[RES:%.*]] = phi i1 [ false, [[MAINBLOCK]] ], [ true, [[START:%.*]] ]
+; CHECK-NEXT: [[RES:%.*]] = phi i1 [ [[CMP]], [[MAINBLOCK]] ], [ true, [[START:%.*]] ]
; CHECK-NEXT: ret i1 [[RES]]
;
start:
Modified: llvm/trunk/test/Transforms/LICM/hoist-mustexec.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/hoist-mustexec.ll?rev=360260&r1=360259&r2=360260&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LICM/hoist-mustexec.ll (original)
+++ llvm/trunk/test/Transforms/LICM/hoist-mustexec.ll Wed May 8 07:50:01 2019
@@ -129,6 +129,8 @@ fail:
}
; requires fact length is non-zero
+; TODO: IsKnownNonNullFromDominatingConditions is currently only be done for
+; pointers; should handle integers too
define i32 @test4(i32* noalias nocapture readonly %a) nounwind uwtable {
; CHECK-LABEL: @test4(
; CHECK-NEXT: entry:
@@ -136,7 +138,6 @@ define i32 @test4(i32* noalias nocapture
; CHECK-NEXT: [[IS_ZERO:%.*]] = icmp eq i32 [[LEN]], 0
; CHECK-NEXT: br i1 [[IS_ZERO]], label [[FAIL:%.*]], label [[PREHEADER:%.*]]
; CHECK: preheader:
-; CHECK-NEXT: [[I1:%.*]] = load i32, i32* [[A]], align 4
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[PREHEADER]] ], [ [[INC:%.*]], [[CONTINUE:%.*]] ]
@@ -144,6 +145,7 @@ define i32 @test4(i32* noalias nocapture
; CHECK-NEXT: [[R_CHK:%.*]] = icmp ult i32 [[IV]], [[LEN]]
; CHECK-NEXT: br i1 [[R_CHK]], label [[CONTINUE]], label [[FAIL_LOOPEXIT:%.*]]
; CHECK: continue:
+; CHECK-NEXT: [[I1:%.*]] = load i32, i32* [[A]], align 4
; CHECK-NEXT: [[ADD]] = add nsw i32 [[I1]], [[ACC]]
; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[IV]], 1
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INC]], 1000
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