diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp index cd50c9756408..d627c3eb5d80 100644 --- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp +++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp @@ -1689,7 +1689,21 @@ void PGOUseFunc::setBranchWeights() { MaxCount = EdgeCount; EdgeCounts[SuccNum] = EdgeCount; } - setProfMetadata(M, TI, EdgeCounts, MaxCount); + + if (MaxCount) + setProfMetadata(M, TI, EdgeCounts, MaxCount); + else { + // A zero MaxCount can come about when we have a BB with a positive + // count, and whose successor blocks all have 0 count. This can happen + // when there is no exit block and the code exits via a noreturn function. + auto &Ctx = M->getContext(); + Ctx.diagnose(DiagnosticInfoPGOProfile( + M->getName().data(), + Twine("Profile in ") + F.getName().str() + + Twine(" partially ignored") + + Twine(", possibly due to the lack of a return path."), + DS_Warning)); + } } } diff --git a/llvm/lib/Transforms/Instrumentation/PGOMemOPSizeOpt.cpp b/llvm/lib/Transforms/Instrumentation/PGOMemOPSizeOpt.cpp index b11f16894669..07c03ee2049a 100644 --- a/llvm/lib/Transforms/Instrumentation/PGOMemOPSizeOpt.cpp +++ b/llvm/lib/Transforms/Instrumentation/PGOMemOPSizeOpt.cpp @@ -440,7 +440,8 @@ bool MemOPSizeOpt::perform(MemOp MO) { DTU.applyUpdates(Updates); Updates.clear(); - setProfMetadata(Func.getParent(), SI, CaseCounts, MaxCount); + if (MaxCount) + setProfMetadata(Func.getParent(), SI, CaseCounts, MaxCount); LLVM_DEBUG(dbgs() << *BB << "\n"); LLVM_DEBUG(dbgs() << *DefaultBB << "\n"); diff --git a/llvm/test/Transforms/PGOProfile/Inputs/maxcountzero.proftext b/llvm/test/Transforms/PGOProfile/Inputs/maxcountzero.proftext new file mode 100755 index 000000000000..d7deb6a40d7b --- /dev/null +++ b/llvm/test/Transforms/PGOProfile/Inputs/maxcountzero.proftext @@ -0,0 +1,11 @@ +# IR level Instrumentation Flag +:ir +foo +# Func Hash: +146835645050580305 +# Num Counters: +3 +# Counter Values: +0 +1 +0 diff --git a/llvm/test/Transforms/PGOProfile/maxcountzero.ll b/llvm/test/Transforms/PGOProfile/maxcountzero.ll new file mode 100755 index 000000000000..1137b2abcef3 --- /dev/null +++ b/llvm/test/Transforms/PGOProfile/maxcountzero.ll @@ -0,0 +1,47 @@ +; Make sure a profile that is generated from a function without an exit node +; does not cause an assertion. The profile consists of a non-zero count in a +; basic block and 0 counts in all succcessor blocks. Expect a warning. + +; RUN: llvm-profdata merge %S/Inputs/maxcountzero.proftext -o %t.profdata +; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S 2>&1 | FileCheck %s + +define void @bar(i32 noundef %s) { +entry: + %cmp = icmp sgt i32 %s, 20 + br i1 %cmp, label %if.then, label %if.end + +if.then: + call void @exit(i32 noundef 1) + unreachable + +if.end: + ret void +} + +declare void @exit(i32 noundef) + +define void @foo(i32 noundef %n) { +entry: + %sum = alloca i32, align 4 + store volatile i32 %n, ptr %sum, align 4 + %sum.0.sum.0. = load volatile i32, ptr %sum, align 4 + call void @bar(i32 noundef %sum.0.sum.0.) + %cmp = icmp slt i32 %n, 10 + br i1 %cmp, label %if.then, label %if.end + +if.then: + %sum.0.sum.0.1 = load volatile i32, ptr %sum, align 4 + call void @bar(i32 noundef %sum.0.sum.0.1) + br label %if.end + +if.end: + br label %for.cond + +for.cond: + %sum.0.sum.0.2 = load volatile i32, ptr %sum, align 4 + call void @bar(i32 noundef %sum.0.sum.0.2) + br label %for.cond +} + +; CHECK: warning:{{.*}}Profile in foo partially ignored +; CHECK: define