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[NewGVN] Update additionalUsers when we simplify to a value.

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Otherwise we don't revisit an instruction that could be simplified,
and when we verify, we discover there's something that changed, i.e.
what we had wasn't a maximal fixpoint.

Fixes PR32836.

llvm-svn: 303715
This commit is contained in:
Davide Italiano 2017-05-24 02:30:24 +00:00
parent db615dd677
commit fd9100e056
2 changed files with 49 additions and 0 deletions
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4
llvm/lib/Transforms/Scalar/NewGVN.cpp
View File

@ -955,6 +955,10 @@ const Expression *NewGVN::checkSimplificationResults(Expression *E,
CongruenceClass *CC = ValueToClass.lookup(V);
if (CC && CC->getDefiningExpr()) {
// If we simplified to something else, we need to communicate
// that we're users of the value we simplified to.
if (I != V)
addAdditionalUsers(V, I);
if (I)
DEBUG(dbgs() << "Simplified " << *I << " to "
<< " expression " << *CC->getDefiningExpr() << "\n");

45
llvm/test/Transforms/NewGVN/pr32836.ll Normal file
View File

@ -0,0 +1,45 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -newgvn %s | FileCheck %s
%struct.anon = type { i32 }
@b = external global %struct.anon
define void @tinkywinky(i1 %patatino) {
; CHECK-LABEL: @tinkywinky(
; CHECK-NEXT: store i32 8, i32* null
; CHECK-NEXT: br i1 [[PATATINO:%.*]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[L:%.*]]
; CHECK: L:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: [[TMP1:%.*]] = load i32, i32* null
; CHECK-NEXT: [[BF_LOAD1:%.*]] = load i32, i32* getelementptr inbounds (%struct.anon, %struct.anon* @b, i64 0, i32 0)
; CHECK-NEXT: [[BF_VALUE:%.*]] = and i32 [[TMP1]], 536870911
; CHECK-NEXT: [[BF_CLEAR:%.*]] = and i32 [[BF_LOAD1]], -536870912
; CHECK-NEXT: [[BF_SET:%.*]] = or i32 [[BF_CLEAR]], [[BF_VALUE]]
; CHECK-NEXT: store i32 [[BF_SET]], i32* getelementptr inbounds (%struct.anon, %struct.anon* @b, i64 0, i32 0)
; CHECK-NEXT: br label [[LOR_END:%.*]]
; CHECK: lor.end:
; CHECK-NEXT: br label [[L]]
;
store i32 8, i32* null
br i1 %patatino, label %if.end, label %if.then
if.then:
store i32 8, i32* null
br label %L
L:
br label %if.end
if.end:
%tmp1 = load i32, i32* null
%bf.load1 = load i32, i32* getelementptr (%struct.anon, %struct.anon* @b, i64 0, i32 0)
%bf.value = and i32 %tmp1, 536870911
%bf.clear = and i32 %bf.load1, -536870912
%bf.set = or i32 %bf.clear, %bf.value
store i32 %bf.set, i32* getelementptr (%struct.anon, %struct.anon* @b, i64 0, i32 0)
br label %lor.end
lor.end:
%bf.load4 = load i32, i32* getelementptr (%struct.anon, %struct.anon* @b, i64 0, i32 0)
%tmp4 = and i32 %bf.load4, 536870911
%or = or i32 0, %tmp4
br label %L
}