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llvm-mirror/test/Transforms/SimplifyCFG/extract-cost.ll
Louis Gerbarg 011e17086c Add ExtractValue instruction to SimplifyCFG's ComputeSpeculationCost
Since ExtractValue is not included in ComputeSpeculationCost CFGs containing
ExtractValueInsts cannot be simplified. In particular this interacts with
InstCombineCompare's tendency to insert add.with.overflow intrinsics for
certain idiomatic math operations, preventing optimization.

This patch adds ExtractValue to the ComputeSpeculationCost. Test case included

rdar://14853450

llvm-svn: 208434
2014-05-09 17:02:46 +00:00

23 lines
650 B
LLVM

; RUN: opt -simplifycfg -S < %s | FileCheck %s
declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32) #1
define i32 @f(i32 %a, i32 %b) #0 {
entry:
%uadd = tail call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
%cmp = extractvalue { i32, i1 } %uadd, 1
br i1 %cmp, label %return, label %if.end
if.end: ; preds = %entry
%0 = extractvalue { i32, i1 } %uadd, 0
br label %return
return: ; preds = %entry, %if.end
%retval.0 = phi i32 [ %0, %if.end ], [ 0, %entry ]
ret i32 %retval.0
; CHECK-LABEL: @f(
; CHECK-NOT: phi
; CHECK: select
}