[AMDGPU][SIPreEmitPeephole] Fix mustRetainExeczBranch

Author: mbrkusanin

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

@@ -362,6 +362,10 @@ bool SIPreEmitPeephole::mustRetainExeczBranch(
       if (MI.isConditionalBranch())
         return true;
 
+      if (MI.isUnconditionalBranch() &&
+          TII->getBranchDestBlock(MI) != MBB.getNextNode())
+        return true;
+
       if (MI.isMetaInstruction())
         continue;
 

llvm/test/CodeGen/AMDGPU/remove-not-short-exec-branch-on-unconditional-jump.mir

@@ -24,10 +24,11 @@ body:             |
   ; CHECK-NEXT:   S_BRANCH %bb.2
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.2:
-  ; CHECK-NEXT:   successors: %bb.3(0x40000000)
+  ; CHECK-NEXT:   successors: %bb.4(0x40000000), %bb.3(0x40000000)
   ; CHECK-NEXT:   liveins: $vgpr1, $sgpr0_sgpr1, $sgpr2_sgpr3, $sgpr4_sgpr5
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   $exec = S_OR_B64 $exec, killed renamable $sgpr4_sgpr5, implicit-def $scc
+  ; CHECK-NEXT:   S_CBRANCH_EXECZ %bb.4, implicit $exec
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.3:
   ; CHECK-NEXT:   successors: %bb.1(0x80000000)