Make tail merging handle blocks with repeated predecessors correctly, and

remove RemoveDuplicateSuccessor, as it is no longer necessary, and because
it breaks assumptions made in
MachineBasicBlock::isOnlyReachableByFallthrough.

Convert test/CodeGen/X86/omit-label.ll to FileCheck and add a testcase
for PR4732.

test/CodeGen/Thumb2/thumb2-ifcvt2.ll sees a diff with this commit due to
it being bugpoint-reduced to the point where it doesn't matter what the
condition for the branch is.

Add some more interesting code to
test/CodeGen/X86/2009-08-06-branchfolder-crash.ll, which is the testcase
that originally motivated the RemoveDuplicateSuccessor code, to help
verify that the original problem isn't being re-broken.

llvm-svn: 79338

1 files changed, 52 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll b/llvm/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
index 5e58725cb99..2c8cf0c8cd5 100644
--- a/llvm/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
+++ b/llvm/test/CodeGen/X86/2009-08-06-branchfolder-crash.ll
@@ -88,3 +88,55 @@ for.inc:		; preds = %for.inc, %lor.end.i, %lor.rhs.i, %land.lhs.true3.i
 }
 
 declare i32 @safe()
+
+define i32 @func_35(i8 signext %p_35) nounwind readonly {
+entry:
+  %tobool = icmp eq i8 %p_35, 0                   ; <i1> [#uses=1]
+  br i1 %tobool, label %lor.lhs.false, label %if.then
+
+lor.lhs.false:                                    ; preds = %entry
+  %tmp1 = load i8* @g_3                           ; <i8> [#uses=1]
+  %tobool3 = icmp eq i8 %tmp1, 0                  ; <i1> [#uses=1]
+  br i1 %tobool3, label %return, label %if.then
+
+if.then:                                          ; preds = %lor.lhs.false, %entry
+  %tmp4 = load i8* @g_3                           ; <i8> [#uses=1]
+  %conv5 = sext i8 %tmp4 to i32                   ; <i32> [#uses=1]
+  ret i32 %conv5
+
+return:                                           ; preds = %lor.lhs.false
+  ret i32 0
+}
+
+define void @bar(i32 %p_5) noreturn nounwind {
+entry:
+  %cmp = icmp sgt i32 %p_5, 0                     ; <i1> [#uses=2]
+  %call = tail call i32 @safe() nounwind          ; <i32> [#uses=1]
+  %conv1 = trunc i32 %call to i8                  ; <i8> [#uses=3]
+  %tobool.i = xor i1 %cmp, true                   ; <i1> [#uses=3]
+  %cmp.i = icmp sgt i8 %conv1, 0                  ; <i1> [#uses=3]
+  %or.cond.i = or i1 %cmp.i, %tobool.i            ; <i1> [#uses=1]
+  br i1 %or.cond.i, label %lor.rhs.i, label %land.lhs.true3.i
+
+land.lhs.true3.i:                                 ; preds = %entry
+  %xor = zext i1 %cmp to i32                      ; <i32> [#uses=1]
+  %conv5.i = sext i8 %conv1 to i32                ; <i32> [#uses=1]
+  %cmp7.i = icmp slt i32 %conv5.i, %xor           ; <i1> [#uses=1]
+  %cmp7.i.not = xor i1 %cmp7.i, true              ; <i1> [#uses=1]
+  %or.cond23.i = and i1 %cmp.i, %tobool.i         ; <i1> [#uses=1]
+  %or.cond = and i1 %cmp7.i.not, %or.cond23.i     ; <i1> [#uses=1]
+  br i1 %or.cond, label %lor.end.i, label %for.inc
+
+lor.rhs.i:                                        ; preds = %entry
+  %or.cond23.i.old = and i1 %cmp.i, %tobool.i     ; <i1> [#uses=1]
+  br i1 %or.cond23.i.old, label %lor.end.i, label %for.inc
+
+lor.end.i:                                        ; preds = %lor.rhs.i, %land.lhs.true3.i
+  %tobool19.i = icmp eq i8 %conv1, 0              ; <i1> [#uses=0]
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.inc, %lor.end.i, %lor.rhs.i, %land.lhs.true3.i
+  br label %for.inc
+}
+
+declare i32 @safe()