X86: Conditional tail calls should not have isBarrier = 1

That confuses e.g. machine basic block placement, which then doesn't
realize that control can fall through a block that ends with a conditional
tail call. Instead, isBranch=1 should be set.

Also, mark EFLAGS as used by these instructions.

llvm-svn: 281281

2 files changed, 31 insertions, 3 deletions

diff --git a/llvm/test/CodeGen/X86/conditional-tailcall.ll b/llvm/test/CodeGen/X86/conditional-tailcall.ll
index 5dfdfd49ceb..502643d9a91 100644
--- a/llvm/test/CodeGen/X86/conditional-tailcall.ll
+++ b/llvm/test/CodeGen/X86/conditional-tailcall.ll
@@ -14,12 +14,40 @@ bb1:
 bb2:
   tail call void @bar()
   ret void
-}
 
 ; CHECK-LABEL: f:
 ; CHECK: cmp
 ; CHECK: jne bar
 ; Check that the asm doesn't just look good, but uses the correct encoding.
 ; CHECK: encoding: [0x75,A]
-
 ; CHECK: jmp foo
+}
+
+
+declare x86_thiscallcc zeroext i1 @baz(i8*, i32)
+define x86_thiscallcc zeroext i1 @BlockPlacementTest(i8* %this, i32 %x) optsize {
+entry:
+  %and = and i32 %x, 42
+  %tobool = icmp eq i32 %and, 0
+  br i1 %tobool, label %land.end, label %land.rhs
+
+land.rhs:
+  %and6 = and i32 %x, 44
+  %tobool7 = icmp eq i32 %and6, 0
+  br i1 %tobool7, label %lor.rhs, label %land.end
+
+lor.rhs:
+  %call = tail call x86_thiscallcc zeroext i1 @baz(i8* %this, i32 %x) #2
+  br label %land.end
+
+land.end:
+  %0 = phi i1 [ false, %entry ], [ true, %land.rhs ], [ %call, %lor.rhs ]
+  ret i1 %0
+
+; Make sure machine block placement isn't confused by the conditional tail call,
+; but sees that it can fall through to the next block.
+; CHECK-LABEL: BlockPlacementTest
+; CHECK: je baz
+; CHECK-NOT: xor
+; CHECK: ret
+}
diff --git a/llvm/test/CodeGen/X86/tail-call-conditional.mir b/llvm/test/CodeGen/X86/tail-call-conditional.mir
index 3646076ccf8..af6e95d4610 100644
--- a/llvm/test/CodeGen/X86/tail-call-conditional.mir
+++ b/llvm/test/CodeGen/X86/tail-call-conditional.mir
@@ -47,7 +47,7 @@ body:             |
   ; CHECK-NEXT: %rdi = COPY %rsi
   ; CHECK-NEXT: %rsi = COPY %rax
   ; CHECK-NEXT: CMP64ri8 %rax, 9, implicit-def %eflags
-  ; CHECK-NEXT: TCRETURNdi64cc @f1, 0, 3, csr_64, implicit %rsp, implicit %rsp, implicit %rdi, implicit %rsi
+  ; CHECK-NEXT: TCRETURNdi64cc @f1, 0, 3, csr_64, implicit %rsp, implicit %eflags, implicit %rsp, implicit %rdi, implicit %rsi
 
   bb.1:
     successors: %bb.2, %bb.3