bpf: J*_RR should check both operands

There is a mistake in current code that we "break" out the optimization
when the first operand of J*_RR doesn't qualify the elimination. This
caused some elimination opportunities missed, for example the one in the
testcase.

The code should just fall through to handle the second operand.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 327366

1 files changed, 4 insertions, 6 deletions

diff --git a/llvm/lib/Target/BPF/BPFMIPeephole.cpp b/llvm/lib/Target/BPF/BPFMIPeephole.cpp
index 3df14b4ad5b..7d84b2834f8 100644
--- a/llvm/lib/Target/BPF/BPFMIPeephole.cpp
+++ b/llvm/lib/Target/BPF/BPFMIPeephole.cpp
@@ -156,12 +156,10 @@ bool BPFMIPeephole::eliminateCmpPromotionSeq(void) {
       case BPF::JNE_rr:
         Reg = MI.getOperand(1).getReg();
         Mov = getInsnDefZExtSubReg(Reg);
-        if (!Mov)
-          break;
-
-	updateInsnSeq(MBB, MI, Reg);
-	Eliminated = true;
-
+        if (Mov) {
+          updateInsnSeq(MBB, MI, Reg);
+          Eliminated = true;
+        }
         // Fallthrough
       case BPF::JUGT_ri:
       case BPF::JUGE_ri: