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-rw-r--r--llvm/test/Transforms/SimplifyCFG/ForwardSwitchConditionToPHI.ll123
1 files changed, 123 insertions, 0 deletions
diff --git a/llvm/test/Transforms/SimplifyCFG/ForwardSwitchConditionToPHI.ll b/llvm/test/Transforms/SimplifyCFG/ForwardSwitchConditionToPHI.ll
new file mode 100644
index 00000000000..169f3f629ea
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/ForwardSwitchConditionToPHI.ll
@@ -0,0 +1,123 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -simplifycfg -forward-switch-cond=false -S | FileCheck %s --check-prefix=NO_FWD
+; RUN: opt < %s -simplifycfg -forward-switch-cond=true -S | FileCheck %s --check-prefix=FWD
+
+; RUN: opt < %s -passes='simplify-cfg<no-forward-switch-cond>' -S | FileCheck %s --check-prefix=NO_FWD
+; RUN: opt < %s -passes='simplify-cfg<forward-switch-cond>' -S | FileCheck %s --check-prefix=FWD
+
+; PR10131
+
+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"
+target triple = "i386-pc-linux-gnu"
+
+define i32 @t(i32 %m) nounwind readnone {
+; NO_FWD-LABEL: @t(
+; NO_FWD-NEXT: entry:
+; NO_FWD-NEXT: switch i32 [[M:%.*]], label [[SW_BB4:%.*]] [
+; NO_FWD-NEXT: i32 0, label [[RETURN:%.*]]
+; NO_FWD-NEXT: i32 1, label [[SW_BB1:%.*]]
+; NO_FWD-NEXT: i32 2, label [[SW_BB2:%.*]]
+; NO_FWD-NEXT: i32 3, label [[SW_BB3:%.*]]
+; NO_FWD-NEXT: ]
+; NO_FWD: sw.bb1:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: sw.bb2:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: sw.bb3:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: sw.bb4:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: return:
+; NO_FWD-NEXT: [[RETVAL_0:%.*]] = phi i32 [ 4, [[SW_BB4]] ], [ 3, [[SW_BB3]] ], [ 2, [[SW_BB2]] ], [ 1, [[SW_BB1]] ], [ 0, [[ENTRY:%.*]] ]
+; NO_FWD-NEXT: ret i32 [[RETVAL_0]]
+;
+; FWD-LABEL: @t(
+; FWD-NEXT: entry:
+; FWD-NEXT: [[SWITCH:%.*]] = icmp ult i32 [[M:%.*]], 4
+; FWD-NEXT: [[M_:%.*]] = select i1 [[SWITCH]], i32 [[M]], i32 4
+; FWD-NEXT: ret i32 [[M_]]
+;
+entry:
+ switch i32 %m, label %sw.bb4 [
+ i32 0, label %sw.bb0
+ i32 1, label %sw.bb1
+ i32 2, label %sw.bb2
+ i32 3, label %sw.bb3
+ ]
+
+sw.bb0: ; preds = %entry
+ br label %return
+
+sw.bb1: ; preds = %entry
+ br label %return
+
+sw.bb2: ; preds = %entry
+ br label %return
+
+sw.bb3: ; preds = %entry
+ br label %return
+
+sw.bb4: ; preds = %entry
+ br label %return
+
+return: ; preds = %entry, %sw.bb4, %sw.bb3, %sw.bb2, %sw.bb1
+ %retval.0 = phi i32 [ 4, %sw.bb4 ], [ 3, %sw.bb3 ], [ 2, %sw.bb2 ], [ 1, %sw.bb1 ], [ 0, %sw.bb0 ]
+ ret i32 %retval.0
+}
+
+; If 1 incoming phi value is a case constant of a switch, convert it to the switch condition:
+; https://bugs.llvm.org/show_bug.cgi?id=34471
+; This then subsequently should allow squashing of the other trivial case blocks.
+
+define i32 @PR34471(i32 %x) {
+; NO_FWD-LABEL: @PR34471(
+; NO_FWD-NEXT: entry:
+; NO_FWD-NEXT: switch i32 [[X:%.*]], label [[ELSE3:%.*]] [
+; NO_FWD-NEXT: i32 17, label [[RETURN:%.*]]
+; NO_FWD-NEXT: i32 19, label [[IF19:%.*]]
+; NO_FWD-NEXT: i32 42, label [[IF42:%.*]]
+; NO_FWD-NEXT: ]
+; NO_FWD: if19:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: if42:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: else3:
+; NO_FWD-NEXT: br label [[RETURN]]
+; NO_FWD: return:
+; NO_FWD-NEXT: [[R:%.*]] = phi i32 [ [[X]], [[IF19]] ], [ [[X]], [[IF42]] ], [ 0, [[ELSE3]] ], [ 17, [[ENTRY:%.*]] ]
+; NO_FWD-NEXT: ret i32 [[R]]
+;
+; FWD-LABEL: @PR34471(
+; FWD-NEXT: entry:
+; FWD-NEXT: switch i32 [[X:%.*]], label [[ELSE3:%.*]] [
+; FWD-NEXT: i32 17, label [[RETURN:%.*]]
+; FWD-NEXT: i32 19, label [[RETURN]]
+; FWD-NEXT: i32 42, label [[RETURN]]
+; FWD-NEXT: ]
+; FWD: else3:
+; FWD-NEXT: br label [[RETURN]]
+; FWD: return:
+; FWD-NEXT: [[R:%.*]] = phi i32 [ 0, [[ELSE3]] ], [ [[X]], [[ENTRY:%.*]] ], [ [[X]], [[ENTRY]] ], [ [[X]], [[ENTRY]] ]
+; FWD-NEXT: ret i32 [[R]]
+;
+entry:
+ switch i32 %x, label %else3 [
+ i32 17, label %return
+ i32 19, label %if19
+ i32 42, label %if42
+ ]
+
+if19:
+ br label %return
+
+if42:
+ br label %return
+
+else3:
+ br label %return
+
+return:
+ %r = phi i32 [ %x, %if19 ], [ %x, %if42 ], [ 0, %else3 ], [ 17, %entry ]
+ ret i32 %r
+}
+
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