fa7367428a
The first variant contains all current transformations except transforming switches into lookup tables. The second variant contains all current transformations. The switch-to-lookup-table conversion results in code that is more difficult to analyze and optimize by other passes. Most importantly, it can inhibit Dead Code Elimination. As such it is often beneficial to only apply this transformation very late. A common example is inlining, which can often result in range restrictions for the switch expression. Changes in execution time according to LNT: SingleSource/Benchmarks/Misc/fp-convert +3.03% MultiSource/Benchmarks/ASC_Sequoia/CrystalMk/CrystalMk -11.20% MultiSource/Benchmarks/Olden/perimeter/perimeter -10.43% and a couple of smaller changes. For perimeter it also results 2.6% a smaller binary. Differential Revision: https://reviews.llvm.org/D30333 llvm-svn: 298799
51 lines
1.4 KiB
LLVM
51 lines
1.4 KiB
LLVM
; RUN: opt -S -latesimplifycfg < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
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; rdar://17887153
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target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
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target triple = "x86_64-apple-darwin12.0.0"
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; When we have a covered lookup table, make sure we don't delete PHINodes that
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; are cached in PHIs.
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; CHECK-LABEL: @test
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; CHECK: entry:
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; CHECK-NEXT: sub i3 %arg, -4
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; CHECK-NEXT: zext i3 %switch.tableidx to i4
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; CHECK-NEXT: getelementptr inbounds [8 x i64], [8 x i64]* @switch.table, i32 0, i4 %switch.tableidx.zext
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; CHECK-NEXT: load i64, i64* %switch.gep
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; CHECK-NEXT: add i64
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; CHECK-NEXT: ret i64
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define i64 @test(i3 %arg) {
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entry:
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switch i3 %arg, label %Default [
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i3 -2, label %Label6
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i3 1, label %Label1
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i3 2, label %Label2
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i3 3, label %Label3
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i3 -4, label %Label4
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i3 -3, label %Label5
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]
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Default:
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%v1 = phi i64 [ 7, %Label6 ], [ 11, %Label5 ], [ 6, %Label4 ], [ 13, %Label3 ], [ 9, %Label2 ], [ 15, %Label1 ], [ 8, %entry ]
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%v2 = phi i64 [ 0, %Label6 ], [ 0, %Label5 ], [ 0, %Label4 ], [ 0, %Label3 ], [ 0, %Label2 ], [ 0, %Label1 ], [ 0, %entry ]
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%v3 = add i64 %v1, %v2
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ret i64 %v3
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Label1:
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br label %Default
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Label2:
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br label %Default
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Label3:
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br label %Default
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Label4:
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br label %Default
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Label5:
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br label %Default
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Label6:
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br label %Default
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}
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