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diff src/share/vm/c1/c1_LinearScan.cpp @ 8860:46f6f063b272

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7153771: array bound check elimination for c1 Summary: when possible optimize out array bound checks, inserting predicates when needed. Reviewed-by: never, kvn, twisti Contributed-by: thomaswue <thomas.wuerthinger@oracle.com>
author roland
date Thu, 21 Mar 2013 09:27:54 +0100
parents b9a9ed0f8eeb
children 9acbfe04b5c3
line wrap: on
line diff
--- a/src/share/vm/c1/c1_LinearScan.cpp	Wed Mar 20 17:04:45 2013 -0700
+++ b/src/share/vm/c1/c1_LinearScan.cpp	Thu Mar 21 09:27:54 2013 +0100
@@ -6231,26 +6231,29 @@
             assert(prev_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
             LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
 
-            LIR_Op2* prev_cmp = NULL;
-
-            for(int j = instructions->length() - 3; j >= 0 && prev_cmp == NULL; j--) {
-              prev_op = instructions->at(j);
-              if(prev_op->code() == lir_cmp) {
-                assert(prev_op->as_Op2() != NULL, "branch must be of type LIR_Op2");
-                prev_cmp = (LIR_Op2*)prev_op;
-                assert(prev_branch->cond() == prev_cmp->condition(), "should be the same");
+            if (prev_branch->stub() == NULL) {
+
+              LIR_Op2* prev_cmp = NULL;
+
+              for(int j = instructions->length() - 3; j >= 0 && prev_cmp == NULL; j--) {
+                prev_op = instructions->at(j);
+                if (prev_op->code() == lir_cmp) {
+                  assert(prev_op->as_Op2() != NULL, "branch must be of type LIR_Op2");
+                  prev_cmp = (LIR_Op2*)prev_op;
+                  assert(prev_branch->cond() == prev_cmp->condition(), "should be the same");
+                }
               }
-            }
-            assert(prev_cmp != NULL, "should have found comp instruction for branch");
-            if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
-
-              TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
-
-              // eliminate a conditional branch to the immediate successor
-              prev_branch->change_block(last_branch->block());
-              prev_branch->negate_cond();
-              prev_cmp->set_condition(prev_branch->cond());
-              instructions->truncate(instructions->length() - 1);
+              assert(prev_cmp != NULL, "should have found comp instruction for branch");
+              if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
+
+                TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
+
+                // eliminate a conditional branch to the immediate successor
+                prev_branch->change_block(last_branch->block());
+                prev_branch->negate_cond();
+                prev_cmp->set_condition(prev_branch->cond());
+                instructions->truncate(instructions->length() - 1);
+              }
             }
           }
         }