Author: lattner Date: Thu Jan 3 01:25:26 2008 New Revision: 45533 URL: http://llvm.org/viewvc/llvm-project?rev=45533&view=rev Log: 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%.
Added: llvm/trunk/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=45533&r1=45532&r2=45533&view=diff ============================================================================== --- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original) +++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Thu Jan 3 01:25:26 2008 @@ -372,6 +372,8 @@ 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. } Added: llvm/trunk/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll?rev=45533&view=auto ============================================================================== --- llvm/trunk/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll (added) +++ llvm/trunk/test/Transforms/SimplifyCFG/2008-01-02-hoist-fp-add.ll Thu Jan 3 01:25:26 2008 @@ -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" [EMAIL PROTECTED] = 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 +} + _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits