summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--llvm/include/llvm/Transforms/Scalar/GVN.h2
-rw-r--r--llvm/lib/Transforms/Scalar/GVN.cpp40
-rw-r--r--llvm/test/Transforms/GVN/pr42605.ll87
3 files changed, 128 insertions, 1 deletions
diff --git a/llvm/include/llvm/Transforms/Scalar/GVN.h b/llvm/include/llvm/Transforms/Scalar/GVN.h
index 2c9287f86cd..e3b4fe4702a 100644
--- a/llvm/include/llvm/Transforms/Scalar/GVN.h
+++ b/llvm/include/llvm/Transforms/Scalar/GVN.h
@@ -120,6 +120,8 @@ public:
uint32_t lookupOrAddCall(CallInst *C);
uint32_t phiTranslateImpl(const BasicBlock *BB, const BasicBlock *PhiBlock,
uint32_t Num, GVN &Gvn);
+ bool areCallValsEqual(uint32_t Num, uint32_t NewNum, const BasicBlock *Pred,
+ const BasicBlock *PhiBlock, GVN &Gvn);
std::pair<uint32_t, bool> assignExpNewValueNum(Expression &exp);
bool areAllValsInBB(uint32_t num, const BasicBlock *BB, GVN &Gvn);
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 65ba0bbc9a7..d2743570d80 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1544,6 +1544,41 @@ uint32_t GVN::ValueTable::phiTranslate(const BasicBlock *Pred,
return NewNum;
}
+// Return true if the value number \p Num and NewNum have equal value.
+// Return false if the result is unknown.
+bool GVN::ValueTable::areCallValsEqual(uint32_t Num, uint32_t NewNum,
+ const BasicBlock *Pred,
+ const BasicBlock *PhiBlock, GVN &Gvn) {
+ CallInst *Call = nullptr;
+ LeaderTableEntry *Vals = &Gvn.LeaderTable[Num];
+ while (Vals) {
+ Call = dyn_cast<CallInst>(Vals->Val);
+ if (Call && Call->getParent() == PhiBlock)
+ break;
+ Vals = Vals->Next;
+ }
+
+ if (AA->doesNotAccessMemory(Call))
+ return true;
+
+ if (!MD || !AA->onlyReadsMemory(Call))
+ return false;
+
+ MemDepResult local_dep = MD->getDependency(Call);
+ if (!local_dep.isNonLocal())
+ return false;
+
+ const MemoryDependenceResults::NonLocalDepInfo &deps =
+ MD->getNonLocalCallDependency(Call);
+
+ // Check to see if the Call has no function local clobber.
+ for (unsigned i = 0; i < deps.size(); i++) {
+ if (deps[i].getResult().isNonFuncLocal())
+ return true;
+ }
+ return false;
+}
+
/// Translate value number \p Num using phis, so that it has the values of
/// the phis in BB.
uint32_t GVN::ValueTable::phiTranslateImpl(const BasicBlock *Pred,
@@ -1590,8 +1625,11 @@ uint32_t GVN::ValueTable::phiTranslateImpl(const BasicBlock *Pred,
}
}
- if (uint32_t NewNum = expressionNumbering[Exp])
+ if (uint32_t NewNum = expressionNumbering[Exp]) {
+ if (Exp.opcode == Instruction::Call && NewNum != Num)
+ return areCallValsEqual(Num, NewNum, Pred, PhiBlock, Gvn) ? NewNum : Num;
return NewNum;
+ }
return Num;
}
diff --git a/llvm/test/Transforms/GVN/pr42605.ll b/llvm/test/Transforms/GVN/pr42605.ll
new file mode 100644
index 00000000000..542f6f9c016
--- /dev/null
+++ b/llvm/test/Transforms/GVN/pr42605.ll
@@ -0,0 +1,87 @@
+; RUN: opt -gvn %s -S | FileCheck %s
+; PR42605. Check phi-translate won't translate the value number of a call
+; to the value of another call with clobber in between.
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@global = dso_local local_unnamed_addr global i32 0, align 4
+@.str = private unnamed_addr constant [8 x i8] c"%d, %d\0A\00", align 1
+
+; Function Attrs: nofree nounwind
+declare dso_local i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr
+
+; Function Attrs: noinline norecurse nounwind readonly uwtable
+define dso_local i32 @_Z3gooi(i32 %i) local_unnamed_addr #0 {
+entry:
+ %t0 = load i32, i32* @global, align 4, !tbaa !2
+ %add = add nsw i32 %t0, %i
+ ret i32 %add
+}
+
+; Function Attrs: nofree nounwind uwtable
+define dso_local void @noclobber() local_unnamed_addr {
+entry:
+ %call = tail call i32 @_Z3gooi(i32 2)
+ %add = add nsw i32 %call, 5
+ %cmp = icmp sgt i32 %add, 2
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ %call1 = tail call i32 @_Z3gooi(i32 3)
+ %add2 = add nsw i32 %call1, 5
+ br label %if.end
+
+; Check pre happens after phitranslate.
+; CHECK-LABEL: @noclobber
+; CHECK: %add4.pre-phi = phi i32 [ %add2, %if.then ], [ %add, %entry ]
+; CHECK: printf(i8* getelementptr inbounds {{.*}}, i32 %add4.pre-phi)
+
+if.end: ; preds = %if.then, %entry
+ %i.0 = phi i32 [ 3, %if.then ], [ 2, %entry ]
+ %global2.0 = phi i32 [ %add2, %if.then ], [ %add, %entry ]
+ %call3 = tail call i32 @_Z3gooi(i32 %i.0)
+ %add4 = add nsw i32 %call3, 5
+ %call5 = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i64 0, i64 0), i32 %global2.0, i32 %add4)
+ ret void
+}
+
+; Function Attrs: nofree nounwind uwtable
+define dso_local void @hasclobber() local_unnamed_addr {
+entry:
+ %call = tail call i32 @_Z3gooi(i32 2)
+ %add = add nsw i32 %call, 5
+ %cmp = icmp sgt i32 %add, 2
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then: ; preds = %entry
+ %call1 = tail call i32 @_Z3gooi(i32 3)
+ %add2 = add nsw i32 %call1, 5
+ br label %if.end
+
+; Check no pre happens.
+; CHECK-LABEL: @hasclobber
+; CHECK: %call3 = tail call i32 @_Z3gooi(i32 %i.0)
+; CHECK-NEXT: %add4 = add nsw i32 %call3, 5
+; CHECK-NEXT: printf(i8* getelementptr inbounds ({{.*}}, i32 %global2.0, i32 %add4)
+
+if.end: ; preds = %if.then, %entry
+ %i.0 = phi i32 [ 3, %if.then ], [ 2, %entry ]
+ %global2.0 = phi i32 [ %add2, %if.then ], [ %add, %entry ]
+ store i32 5, i32* @global, align 4, !tbaa !2
+ %call3 = tail call i32 @_Z3gooi(i32 %i.0)
+ %add4 = add nsw i32 %call3, 5
+ %call5 = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i64 0, i64 0), i32 %global2.0, i32 %add4)
+ ret void
+}
+
+attributes #0 = { noinline norecurse nounwind readonly uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{!"clang version 10.0.0 (trunk 369798)"}
+!2 = !{!3, !3, i64 0}
+!3 = !{!"int", !4, i64 0}
+!4 = !{!"omnipotent char", !5, i64 0}
+!5 = !{!"Simple C++ TBAA"}
OpenPOWER on IntegriCloud