1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: opt < %s -simplifycfg -forward-switch-cond=false -S | FileCheck %s --check-prefix=NO_FWD 3; RUN: opt < %s -simplifycfg -forward-switch-cond=true -S | FileCheck %s --check-prefix=FWD 4 5; PR10131 6 7target 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" 8target triple = "i386-pc-linux-gnu" 9 10define i32 @t(i32 %m) nounwind readnone { 11; NO_FWD-LABEL: @t( 12; NO_FWD-NEXT: entry: 13; NO_FWD-NEXT: switch i32 [[M:%.*]], label [[SW_BB4:%.*]] [ 14; NO_FWD-NEXT: i32 0, label [[RETURN:%.*]] 15; NO_FWD-NEXT: i32 1, label [[SW_BB1:%.*]] 16; NO_FWD-NEXT: i32 2, label [[SW_BB2:%.*]] 17; NO_FWD-NEXT: i32 3, label [[SW_BB3:%.*]] 18; NO_FWD-NEXT: ] 19; NO_FWD: sw.bb1: 20; NO_FWD-NEXT: br label [[RETURN]] 21; NO_FWD: sw.bb2: 22; NO_FWD-NEXT: br label [[RETURN]] 23; NO_FWD: sw.bb3: 24; NO_FWD-NEXT: br label [[RETURN]] 25; NO_FWD: sw.bb4: 26; NO_FWD-NEXT: br label [[RETURN]] 27; NO_FWD: return: 28; NO_FWD-NEXT: [[RETVAL_0:%.*]] = phi i32 [ 4, [[SW_BB4]] ], [ 3, [[SW_BB3]] ], [ 2, [[SW_BB2]] ], [ 1, [[SW_BB1]] ], [ 0, [[ENTRY:%.*]] ] 29; NO_FWD-NEXT: ret i32 [[RETVAL_0]] 30; 31; FWD-LABEL: @t( 32; FWD-NEXT: entry: 33; FWD-NEXT: [[SWITCH:%.*]] = icmp ult i32 [[M:%.*]], 4 34; FWD-NEXT: [[M_:%.*]] = select i1 [[SWITCH]], i32 [[M]], i32 4 35; FWD-NEXT: ret i32 [[M_]] 36; 37entry: 38 switch i32 %m, label %sw.bb4 [ 39 i32 0, label %sw.bb0 40 i32 1, label %sw.bb1 41 i32 2, label %sw.bb2 42 i32 3, label %sw.bb3 43 ] 44 45sw.bb0: ; preds = %entry 46 br label %return 47 48sw.bb1: ; preds = %entry 49 br label %return 50 51sw.bb2: ; preds = %entry 52 br label %return 53 54sw.bb3: ; preds = %entry 55 br label %return 56 57sw.bb4: ; preds = %entry 58 br label %return 59 60return: ; preds = %entry, %sw.bb4, %sw.bb3, %sw.bb2, %sw.bb1 61 %retval.0 = phi i32 [ 4, %sw.bb4 ], [ 3, %sw.bb3 ], [ 2, %sw.bb2 ], [ 1, %sw.bb1 ], [ 0, %sw.bb0 ] 62 ret i32 %retval.0 63} 64 65; If 1 incoming phi value is a case constant of a switch, convert it to the switch condition: 66; https://bugs.llvm.org/show_bug.cgi?id=34471 67; This then subsequently should allow squashing of the other trivial case blocks. 68 69define i32 @PR34471(i32 %x) { 70; NO_FWD-LABEL: @PR34471( 71; NO_FWD-NEXT: entry: 72; NO_FWD-NEXT: switch i32 [[X:%.*]], label [[ELSE3:%.*]] [ 73; NO_FWD-NEXT: i32 17, label [[RETURN:%.*]] 74; NO_FWD-NEXT: i32 19, label [[IF19:%.*]] 75; NO_FWD-NEXT: i32 42, label [[IF42:%.*]] 76; NO_FWD-NEXT: ] 77; NO_FWD: if19: 78; NO_FWD-NEXT: br label [[RETURN]] 79; NO_FWD: if42: 80; NO_FWD-NEXT: br label [[RETURN]] 81; NO_FWD: else3: 82; NO_FWD-NEXT: br label [[RETURN]] 83; NO_FWD: return: 84; NO_FWD-NEXT: [[R:%.*]] = phi i32 [ [[X]], [[IF19]] ], [ [[X]], [[IF42]] ], [ 0, [[ELSE3]] ], [ 17, [[ENTRY:%.*]] ] 85; NO_FWD-NEXT: ret i32 [[R]] 86; 87; FWD-LABEL: @PR34471( 88; FWD-NEXT: entry: 89; FWD-NEXT: switch i32 [[X:%.*]], label [[ELSE3:%.*]] [ 90; FWD-NEXT: i32 17, label [[RETURN:%.*]] 91; FWD-NEXT: i32 19, label [[RETURN]] 92; FWD-NEXT: i32 42, label [[RETURN]] 93; FWD-NEXT: ] 94; FWD: else3: 95; FWD-NEXT: br label [[RETURN]] 96; FWD: return: 97; FWD-NEXT: [[R:%.*]] = phi i32 [ 0, [[ELSE3]] ], [ [[X]], [[ENTRY:%.*]] ], [ [[X]], [[ENTRY]] ], [ [[X]], [[ENTRY]] ] 98; FWD-NEXT: ret i32 [[R]] 99; 100entry: 101 switch i32 %x, label %else3 [ 102 i32 17, label %return 103 i32 19, label %if19 104 i32 42, label %if42 105 ] 106 107if19: 108 br label %return 109 110if42: 111 br label %return 112 113else3: 114 br label %return 115 116return: 117 %r = phi i32 [ %x, %if19 ], [ %x, %if42 ], [ 0, %else3 ], [ 17, %entry ] 118 ret i32 %r 119} 120 121