Revert r287553: [CodeGenPrep] Skip merging empty case blocks

It results in assertions in lib/Analysis/BlockFrequencyInfoImpl.cpp line
670 ("Expected irreducible CFG").

llvm-svn: 288052

3 files changed, 6 insertions, 150 deletions

diff --git a/llvm/test/Transforms/CodeGenPrepare/AArch64/widen_switch.ll b/llvm/test/Transforms/CodeGenPrepare/AArch64/widen_switch.ll
index cae1cc54a96..172541a4608 100644
--- a/llvm/test/Transforms/CodeGenPrepare/AArch64/widen_switch.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/AArch64/widen_switch.ll
@@ -28,7 +28,7 @@ return:
 ; ARM64-LABEL: @widen_switch_i16(
 ; ARM64:       %0 = zext i16 %trunc to i32
 ; ARM64-NEXT:  switch i32 %0, label %sw.default [
-; ARM64-NEXT:    i32 1, label %sw.bb0
+; ARM64-NEXT:    i32 1, label %return
 ; ARM64-NEXT:    i32 65535, label %sw.bb1
 }
 
@@ -58,7 +58,7 @@ return:
 ; ARM64-LABEL: @widen_switch_i17(
 ; ARM64:       %0 = zext i17 %trunc to i32
 ; ARM64-NEXT:  switch i32 %0, label %sw.default [
-; ARM64-NEXT:    i32 10, label %sw.bb0
+; ARM64-NEXT:    i32 10, label %return
 ; ARM64-NEXT:    i32 131071, label %sw.bb1
 }
 
@@ -89,7 +89,7 @@ return:
 ; ARM64-LABEL: @widen_switch_i16_sext(
 ; ARM64:       %0 = sext i2 %a to i32
 ; ARM64-NEXT:  switch i32 %0, label %sw.default [
-; ARM64-NEXT:    i32 1, label %sw.bb0
+; ARM64-NEXT:    i32 1, label %return
 ; ARM64-NEXT:    i32 -1, label %sw.bb1
 }
 
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/widen_switch.ll b/llvm/test/Transforms/CodeGenPrepare/X86/widen_switch.ll
index 23f120f1a23..53c9cc07355 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/widen_switch.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/widen_switch.ll
@@ -28,7 +28,7 @@ return:
 ; X86-LABEL: @widen_switch_i16(
 ; X86:       %trunc = trunc i32 %a to i16
 ; X86-NEXT:  switch i16 %trunc, label %sw.default [
-; X86-NEXT:    i16 1, label %sw.bb0
+; X86-NEXT:    i16 1, label %return
 ; X86-NEXT:    i16 -1, label %sw.bb1
 }
 
@@ -58,7 +58,7 @@ return:
 ; X86-LABEL: @widen_switch_i17(
 ; X86:       %0 = zext i17 %trunc to i32
 ; X86-NEXT:  switch i32 %0, label %sw.default [
-; X86-NEXT:    i32 10, label %sw.bb0
+; X86-NEXT:    i32 10, label %return
 ; X86-NEXT:    i32 131071, label %sw.bb1
 }
 
@@ -89,7 +89,7 @@ return:
 ; X86-LABEL: @widen_switch_i16_sext(
 ; X86:       %0 = sext i2 %a to i8
 ; X86-NEXT:  switch i8 %0, label %sw.default [
-; X86-NEXT:    i8 1, label %sw.bb0
+; X86-NEXT:    i8 1, label %return
 ; X86-NEXT:    i8 -1, label %sw.bb1
 }
 
diff --git a/llvm/test/Transforms/CodeGenPrepare/skip-merging-case-block.ll b/llvm/test/Transforms/CodeGenPrepare/skip-merging-case-block.ll
deleted file mode 100644
index 3b14aed6eb0..00000000000
--- a/llvm/test/Transforms/CodeGenPrepare/skip-merging-case-block.ll
+++ /dev/null
@@ -1,144 +0,0 @@
-; RUN: opt -codegenprepare  < %s  -mtriple=aarch64-none-linux-gnu -S  | FileCheck %s
-
-target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
-target triple = "aarch64--linux-gnu"
-
-; Expect to skip merging two empty blocks (sw.bb and sw.bb2) into sw.epilog
-; as both of them are unlikely executed.
-define i32 @f_switch(i32 %c)  {
-; CHECK-LABEL: @f_switch
-; CHECK-LABEL: entry:
-; CHECK: i32 10, label %sw.bb
-; CHECK: i32 20, label %sw.bb2
-entry:
-  switch i32 %c, label %sw.default [
-    i32 10, label %sw.bb
-    i32 20, label %sw.bb2
-    i32 30, label %sw.bb3
-    i32 40, label %sw.bb4
-  ], !prof !0
-
-sw.bb:                                            ; preds = %entry
-  br label %sw.epilog
-
-sw.bb2:                                           ; preds = %entry
-  br label %sw.epilog
-
-sw.bb3:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase3 to void ()*)()
-  br label %sw.epilog
-
-sw.bb4:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase4 to void ()*)()
-  br label %sw.epilog
-
-sw.default:                                       ; preds = %entry
-  call void bitcast (void (...)* @calldefault to void ()*)()
-  br label %sw.epilog
-
-; CHECK-LABEL: sw.epilog:
-; CHECK: %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F2, %sw.bb2 ], [ @F1, %sw.bb ]
-sw.epilog:                                        ; preds = %sw.default, %sw.bb3, %sw.bb2, %sw.bb
-  %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F2, %sw.bb2 ], [ @F1, %sw.bb ]
-  %callee.knr.cast = bitcast void (...)* %fp.0 to void ()*
-  call void %callee.knr.cast()
-  ret i32 0
-}
-
-; Expect not to merge sw.bb2 because of the conflict in the incoming value from
-; sw.bb which is already merged.
-define i32 @f_switch2(i32 %c)  {
-; CHECK-LABEL: @f_switch2
-; CHECK-LABEL: entry:
-; CHECK: i32 10, label %sw.epilog
-; CHECK: i32 20, label %sw.bb2
-entry:
-  switch i32 %c, label %sw.default [
-    i32 10, label %sw.bb
-    i32 20, label %sw.bb2
-    i32 30, label %sw.bb3
-    i32 40, label %sw.bb4
-  ], !prof !1
-
-sw.bb:                                            ; preds = %entry
-  br label %sw.epilog
-
-sw.bb2:                                           ; preds = %entry
-  br label %sw.epilog
-
-sw.bb3:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase3 to void ()*)()
-  br label %sw.epilog
-
-sw.bb4:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase4 to void ()*)()
-  br label %sw.epilog
-
-sw.default:                                       ; preds = %entry
-  call void bitcast (void (...)* @calldefault to void ()*)()
-  br label %sw.epilog
-
-; CHECK-LABEL: sw.epilog:
-; CHECK: %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F2, %sw.bb2 ], [ @F1, %entry ]
-sw.epilog:                                        ; preds = %sw.default, %sw.bb3, %sw.bb2, %sw.bb
-  %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F2, %sw.bb2 ], [ @F1, %sw.bb ]
-  %callee.knr.cast = bitcast void (...)* %fp.0 to void ()*
-  call void %callee.knr.cast()
-  ret i32 0
-}
-
-; Multiple empty blocks should be considered together if all incoming values
-; from them are same.  We expect to merge both empty blocks (sw.bb and sw.bb2)
-; because the sum of frequencies are higer than the threshold.
-define i32 @f_switch3(i32 %c)  {
-; CHECK-LABEL: @f_switch3
-; CHECK-LABEL: entry:
-; CHECK: i32 10, label %sw.epilog
-; CHECK: i32 20, label %sw.epilog
-entry:
-  switch i32 %c, label %sw.default [
-    i32 10, label %sw.bb
-    i32 20, label %sw.bb2
-    i32 30, label %sw.bb3
-    i32 40, label %sw.bb4
-  ], !prof !2
-
-sw.bb:                                            ; preds = %entry
-  br label %sw.epilog
-
-sw.bb2:                                           ; preds = %entry
-  br label %sw.epilog
-
-sw.bb3:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase3 to void ()*)()
-  br label %sw.epilog
-
-sw.bb4:                                           ; preds = %entry
-  call void bitcast (void (...)* @callcase4 to void ()*)()
-  br label %sw.epilog
-
-sw.default:                                       ; preds = %entry
-  call void bitcast (void (...)* @calldefault to void ()*)()
-  br label %sw.epilog
-
-; CHECK-LABEL: sw.epilog:
-; CHECK: %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F1, %entry ], [ @F1, %entry ]
-sw.epilog:                                        ; preds = %sw.default, %sw.bb3, %sw.bb2, %sw.bb
-  %fp.0 = phi void (...)* [ @FD, %sw.default ], [ @F4, %sw.bb4 ], [ @F3, %sw.bb3 ], [ @F1, %sw.bb2 ], [ @F1, %sw.bb ]
-  %callee.knr.cast = bitcast void (...)* %fp.0 to void ()*
-  call void %callee.knr.cast()
-  ret i32 0
-}
-
-declare void @F1(...) local_unnamed_addr
-declare void @F2(...) local_unnamed_addr
-declare void @F3(...) local_unnamed_addr
-declare void @F4(...) local_unnamed_addr
-declare void @FD(...) local_unnamed_addr
-declare void @callcase3(...) local_unnamed_addr
-declare void @callcase4(...) local_unnamed_addr
-declare void @calldefault(...) local_unnamed_addr
-
-!0 = !{!"branch_weights", i32 5, i32 1, i32 1,i32 5, i32 5}
-!1 = !{!"branch_weights", i32 1 , i32 5, i32 1,i32 1, i32 1}
-!2 = !{!"branch_weights", i32 1 , i32 4, i32 1,i32 1, i32 1}