# HG changeset patch
# User rkennke
# Date 1541590785 -3600
#      Wed Nov 07 12:39:45 2018 +0100
# Node ID 454fb9961f0f3d9ea2835da2a4f8c2f820f8315f
# Parent  b64514ff68fd794e4464c764407a0dd206561855
8213473: Prevent transformation of LoadB->AndI->CmpI pattern to facilitate testb instruction matching

diff --git a/src/hotspot/share/opto/mulnode.cpp b/src/hotspot/share/opto/mulnode.cpp
--- a/src/hotspot/share/opto/mulnode.cpp
+++ b/src/hotspot/share/opto/mulnode.cpp
@@ -490,7 +490,10 @@
 
     // Masking sign bits off of a Byte?  Do an unsigned byte load plus
     // an and.
-    if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
+    // Prevent transform if it feeds to CmpI. We have special matcher
+    // for LoadB+AndI+CmpI that generates a single instruction.
+    bool feeds_to_cmpi = outcnt() == 1 && unique_out()->Opcode() == Op_CmpI;
+    if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0 && !feeds_to_cmpi) {
       Node* ldub = load->as_Load()->convert_to_unsigned_load(*phase);
       ldub = phase->transform(ldub);
       return new AndINode(ldub, phase->intcon(mask));