diff options
| -rw-r--r-- | docs/LangRef.rst | 4 | ||||
| -rw-r--r-- | lib/Transforms/Utils/LowerExpectIntrinsic.cpp | 23 | ||||
| -rw-r--r-- | test/Transforms/LowerExpectIntrinsic/basic.ll | 29 |
3 files changed, 51 insertions, 5 deletions
diff --git a/docs/LangRef.rst b/docs/LangRef.rst index e1880f2bc1..52f916e237 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -8975,8 +8975,12 @@ on the ``min`` argument). Syntax: """"""" +This is an overloaded intrinsic. You can use ``llvm.expect`` on any +integer bit width. + :: + declare i1 @llvm.expect.i1(i1 <val>, i1 <expected_val>) declare i32 @llvm.expect.i32(i32 <val>, i32 <expected_val>) declare i64 @llvm.expect.i64(i64 <val>, i64 <expected_val>) diff --git a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp index e017f50120..596fd37115 100644 --- a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp +++ b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp @@ -94,15 +94,25 @@ bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) { return false; // Handle non-optimized IR code like: - // %expval = call i64 @llvm.expect.i64.i64(i64 %conv1, i64 1) + // %expval = call i64 @llvm.expect.i64(i64 %conv1, i64 1) // %tobool = icmp ne i64 %expval, 0 // br i1 %tobool, label %if.then, label %if.end + // + // Or the following simpler case: + // %expval = call i1 @llvm.expect.i1(i1 %cmp, i1 1) + // br i1 %expval, label %if.then, label %if.end + + CallInst *CI; ICmpInst *CmpI = dyn_cast<ICmpInst>(BI->getCondition()); - if (!CmpI || CmpI->getPredicate() != CmpInst::ICMP_NE) - return false; + if (!CmpI) { + CI = dyn_cast<CallInst>(BI->getCondition()); + } else { + if (CmpI->getPredicate() != CmpInst::ICMP_NE) + return false; + CI = dyn_cast<CallInst>(CmpI->getOperand(0)); + } - CallInst *CI = dyn_cast<CallInst>(CmpI->getOperand(0)); if (!CI) return false; @@ -127,7 +137,10 @@ bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) { BI->setMetadata(LLVMContext::MD_prof, Node); - CmpI->setOperand(0, ArgValue); + if (CmpI) + CmpI->setOperand(0, ArgValue); + else + BI->setCondition(ArgValue); return true; } diff --git a/test/Transforms/LowerExpectIntrinsic/basic.ll b/test/Transforms/LowerExpectIntrinsic/basic.ll index 955209af14..e184cb05b9 100644 --- a/test/Transforms/LowerExpectIntrinsic/basic.ll +++ b/test/Transforms/LowerExpectIntrinsic/basic.ll @@ -245,6 +245,35 @@ return: ; preds = %if.end, %if.then declare i32 @llvm.expect.i32(i32, i32) nounwind readnone +; CHECK-LABEL: @test9( +define i32 @test9(i32 %x) nounwind uwtable ssp { +entry: + %retval = alloca i32, align 4 + %x.addr = alloca i32, align 4 + store i32 %x, i32* %x.addr, align 4 + %tmp = load i32* %x.addr, align 4 + %cmp = icmp sgt i32 %tmp, 1 + %expval = call i1 @llvm.expect.i1(i1 %cmp, i1 1) +; CHECK: !prof !0 +; CHECK-NOT: @llvm.expect + br i1 %expval, label %if.then, label %if.end + +if.then: ; preds = %entry + %call = call i32 (...)* @f() + store i32 %call, i32* %retval + br label %return + +if.end: ; preds = %entry + store i32 1, i32* %retval + br label %return + +return: ; preds = %if.end, %if.then + %0 = load i32* %retval + ret i32 %0 +} + +declare i1 @llvm.expect.i1(i1, i1) nounwind readnone + ; CHECK: !0 = metadata !{metadata !"branch_weights", i32 64, i32 4} ; CHECK: !1 = metadata !{metadata !"branch_weights", i32 4, i32 64} ; CHECK: !2 = metadata !{metadata !"branch_weights", i32 4, i32 64, i32 4} |