[BOLT] Check for !isTailCall in isUnconditionalBranch

Add !isTailCall in isUnconditionalBranch check in order to sync the x86
and aarch64 and fix the fixDoubleJumps pass on aarch64.

Vladislav Khmelevsky,
Advanced Software Technology Lab, Huawei

Differential Revision: https://reviews.llvm.org/D122929

3 files changed, 32 insertions, 5 deletions

diff --git a/bolt/include/bolt/Core/MCPlusBuilder.h b/bolt/include/bolt/Core/MCPlusBuilder.h
index fae655e119d1..02588c29462a 100644
--- a/bolt/include/bolt/Core/MCPlusBuilder.h
+++ b/bolt/include/bolt/Core/MCPlusBuilder.h
@@ -353,7 +353,7 @@ public:
   }
 
   virtual bool isUnconditionalBranch(const MCInst &Inst) const {
-    return Analysis->isUnconditionalBranch(Inst);
+    return Analysis->isUnconditionalBranch(Inst) && !isTailCall(Inst);
   }
 
   virtual bool isIndirectBranch(const MCInst &Inst) const {
diff --git a/bolt/lib/Target/X86/X86MCPlusBuilder.cpp b/bolt/lib/Target/X86/X86MCPlusBuilder.cpp
index ef6ae1e500ee..b7678cbff06b 100644
--- a/bolt/lib/Target/X86/X86MCPlusBuilder.cpp
+++ b/bolt/lib/Target/X86/X86MCPlusBuilder.cpp
@@ -78,10 +78,6 @@ public:
     return Analysis->isBranch(Inst) && !isTailCall(Inst);
   }
 
-  bool isUnconditionalBranch(const MCInst &Inst) const override {
-    return Analysis->isUnconditionalBranch(Inst) && !isTailCall(Inst);
-  }
-
   bool isNoop(const MCInst &Inst) const override {
     return X86::isNOP(Inst.getOpcode());
   }
diff --git a/bolt/test/AArch64/ext-double-jump.s b/bolt/test/AArch64/ext-double-jump.s
new file mode 100644
index 000000000000..a039cd424c9e
--- /dev/null
+++ b/bolt/test/AArch64/ext-double-jump.s
@@ -0,0 +1,31 @@
+# This test checks that remove double jumps pass works properly with
+# non-local branches.
+
+# RUN: llvm-mc -filetype=obj -triple aarch64-unknown-unknown %s -o %t.o
+# RUN: %clang %cflags -nostartfiles -nodefaultlibs %t.o -o %t.exe -Wl,-q
+# RUN: llvm-bolt %t.exe -o %t.bolt -peepholes=double-jumps
+
+  .text
+  .align 4
+  .global dummy1
+  .type dummy1, %function
+dummy1:
+  mov x2, x0
+  ret
+  .size dummy1, .-dummy1
+
+  .global dummy2
+  .type dummy2, %function
+dummy2:
+  mov x1, x0
+  ret
+  .size dummy2, .-dummy2
+
+  .global _start
+  .type _start, %function
+_start:
+  cbz  x10, 1f
+  b dummy1
+1:
+  b dummy2
+  .size _start, .-_start