diff options
| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-02-24 23:26:09 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-02-24 23:26:09 +0000 |
| commit | 9ae59e3444630419cebea753d65d88f897e586b9 (patch) | |
| tree | 936b2b6f154cecf059c2ac74cfbd0b68f6064c45 | |
| parent | 107d366df762c18294dc00f5de916f62672353ff (diff) | |
SimplifyCFG: GEPs with just one non-constant index are also cheap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126452 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/select-gep.ll | 24 |
2 files changed, 27 insertions, 5 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index c6708857cb..3968d6e8d3 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -247,11 +247,13 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB, if (PBB->getFirstNonPHIOrDbg() != I) return false; break; - case Instruction::GetElementPtr: - // GEPs are cheap if all indices are constant. - if (!cast<GetElementPtrInst>(I)->hasAllConstantIndices()) + case Instruction::GetElementPtr: { + // GEPs are cheap if all indices are constant or if there's only one index. + GetElementPtrInst *GEP = cast<GetElementPtrInst>(I); + if (!GEP->hasAllConstantIndices() && GEP->getNumIndices() > 1) return false; break; + } case Instruction::Add: case Instruction::Sub: case Instruction::And: diff --git a/test/Transforms/SimplifyCFG/select-gep.ll b/test/Transforms/SimplifyCFG/select-gep.ll index 6330ccdb29..98650f0866 100644 --- a/test/Transforms/SimplifyCFG/select-gep.ll +++ b/test/Transforms/SimplifyCFG/select-gep.ll @@ -1,13 +1,13 @@ ; RUN: opt -S -simplifycfg %s | FileCheck %s -define i8* @test1(i8* %x) nounwind { +define i8* @test1(i8* %x, i64 %y) nounwind { entry: %tmp1 = load i8* %x, align 1 %cmp = icmp eq i8 %tmp1, 47 br i1 %cmp, label %if.then, label %if.end if.then: - %incdec.ptr = getelementptr inbounds i8* %x, i64 1 + %incdec.ptr = getelementptr inbounds i8* %x, i64 %y br label %if.end if.end: @@ -18,3 +18,23 @@ if.end: ; CHECK: %x.addr = select i1 %cmp, i8* %incdec.ptr, i8* %x ; CHECK: ret i8* %x.addr } + +%ST = type { i8, i8 } + +define i8* @test2(%ST* %x, i8* %y) nounwind { +entry: + %cmp = icmp eq %ST* %x, null + br i1 %cmp, label %if.then, label %if.end + +if.then: + %incdec.ptr = getelementptr %ST* %x, i32 0, i32 1 + br label %if.end + +if.end: + %x.addr = phi i8* [ %incdec.ptr, %if.then ], [ %y, %entry ] + ret i8* %x.addr + +; CHECK: @test2 +; CHECK: %x.addr = select i1 %cmp, i8* %incdec.ptr, i8* %y +; CHECK: ret i8* %x.addr +} |