diff options
| author | Chris Lattner <sabre@nondot.org> | 2008-01-03 07:25:26 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-01-03 07:25:26 +0000 |
| commit | 3d73bce2d01c7537042bb214edb5fc597f07bf74 (patch) | |
| tree | 00c12eee5788657b4eeeac62f8f91c00c7090583 | |
| parent | 76327d9cf598a17eb69ea928ca43fbacb6cc535e (diff) | |
don't hoist FP additions into unconditional adds + selects. This
could theoretically introduce a trap, but is also a performance issue.
This speeds up ptrdist/ks by 8%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45533 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 2 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll | 26 |
2 files changed, 28 insertions, 0 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index b838f94b79..f19adbd263 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -372,6 +372,8 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB, case Instruction::AShr: case Instruction::ICmp: case Instruction::FCmp: + if (I->getOperand(0)->getType()->isFPOrFPVector()) + return false; // FP arithmetic might trap. break; // These are all cheap and non-trapping instructions. } diff --git a/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll b/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll new file mode 100644 index 0000000000..43ff690150 --- /dev/null +++ b/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll @@ -0,0 +1,26 @@ +; The phi should not be eliminated in this case, because the fp op could trap. +; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep {= phi double} + +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i686-apple-darwin8" +@G = weak global double 0.000000e+00, align 8 ; <double*> [#uses=2] + +define void @test(i32 %X, i32 %Y, double %Z) { +entry: + %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0] + %tmp = load double* @G, align 8 ; <double> [#uses=2] + %tmp3 = icmp eq i32 %X, %Y ; <i1> [#uses=1] + %tmp34 = zext i1 %tmp3 to i8 ; <i8> [#uses=1] + %toBool = icmp ne i8 %tmp34, 0 ; <i1> [#uses=1] + br i1 %toBool, label %cond_true, label %cond_next + +cond_true: ; preds = %entry + %tmp7 = add double %tmp, %Z ; <double> [#uses=1] + br label %cond_next + +cond_next: ; preds = %cond_true, %entry + %F.0 = phi double [ %tmp, %entry ], [ %tmp7, %cond_true ] ; <double> [#uses=1] + store double %F.0, double* @G, align 8 + ret void +} + |