b80daf0b48
As discussed in D39011: https://reviews.llvm.org/D39011 ...replacing constants with a variable is inverting the transform done by other IR passes, so we definitely don't want to do this early. In fact, it's questionable whether this transform belongs in SimplifyCFG at all. I'll look at moving this to codegen as a follow-up step. llvm-svn: 316298
83 lines
2.4 KiB
LLVM
83 lines
2.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -latesimplifycfg -S | FileCheck %s
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; PR10131
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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-f80:32:32-n8:16:32"
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target triple = "i386-pc-linux-gnu"
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define i32 @t(i32 %m) nounwind readnone {
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; CHECK-LABEL: @t(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[SWITCH:%.*]] = icmp ult i32 [[M:%.*]], 4
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; CHECK-NEXT: [[M_:%.*]] = select i1 [[SWITCH]], i32 [[M]], i32 4
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; CHECK-NEXT: ret i32 [[M_]]
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;
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entry:
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switch i32 %m, label %sw.bb4 [
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i32 0, label %sw.bb0
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i32 1, label %sw.bb1
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i32 2, label %sw.bb2
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i32 3, label %sw.bb3
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]
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sw.bb0: ; preds = %entry
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br label %return
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sw.bb1: ; preds = %entry
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br label %return
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sw.bb2: ; preds = %entry
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br label %return
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sw.bb3: ; preds = %entry
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br label %return
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sw.bb4: ; preds = %entry
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br label %return
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return: ; preds = %entry, %sw.bb4, %sw.bb3, %sw.bb2, %sw.bb1
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%retval.0 = phi i32 [ 4, %sw.bb4 ], [ 3, %sw.bb3 ], [ 2, %sw.bb2 ], [ 1, %sw.bb1 ], [ 0, %sw.bb0 ]
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ret i32 %retval.0
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}
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; If 1 incoming phi value is a case constant of a switch, convert it to the switch condition:
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; https://bugs.llvm.org/show_bug.cgi?id=34471
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; This then subsequently should allow squashing of the other trivial case blocks.
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define i32 @PR34471(i32 %x) {
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; CHECK-LABEL: @PR34471(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: switch i32 [[X:%.*]], label [[ELSE3:%.*]] [
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; CHECK-NEXT: i32 17, label [[RETURN:%.*]]
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; CHECK-NEXT: i32 19, label [[RETURN]]
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; CHECK-NEXT: i32 42, label [[RETURN]]
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; CHECK-NEXT: ]
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; CHECK: else3:
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; CHECK-NEXT: br label [[RETURN]]
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; CHECK: return:
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; CHECK-NEXT: [[R:%.*]] = phi i32 [ 0, [[ELSE3]] ], [ [[X]], [[ENTRY:%.*]] ], [ [[X]], [[ENTRY]] ], [ [[X]], [[ENTRY]] ]
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; CHECK-NEXT: ret i32 [[R]]
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;
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entry:
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switch i32 %x, label %else3 [
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i32 17, label %return
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i32 19, label %if19
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i32 42, label %if42
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]
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if19:
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br label %return
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if42:
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br label %return
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else3:
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br label %return
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return:
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%r = phi i32 [ %x, %if19 ], [ %x, %if42 ], [ 0, %else3 ], [ 17, %entry ]
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ret i32 %r
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}
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