My commit r240439 didn't handle the situation where setting
--param prefetch-latency=0 can cause the prefetch address to
be the same as the original address. In this case, no
copying of points-to information should be done.
Bootstrapped and regression tested on x86_64-linux, ok for
trunk?
Doug
From d7a115e12856f2bcd4cefab38378f5d947c7d96a Mon Sep 17 00:00:00 2001
From: Doug Gilmore <doug.gilm...@imgtec.com>
Date: Fri, 30 Sep 2016 11:28:20 -0700
Subject: [PATCH] Fix PR tree-optimization/77808
gcc/
PR tree-optimization/77808
* tree-ssa-loop-prefetch.c (issue_prefetch_ref): Fix problem
exposed by specifying --param prefetch-latency=0.
gcc/testsuite
PR tree-optimization/77808
* gcc.dg/tree-ssa/pr77808.c: New testcase.
---
gcc/testsuite/gcc.dg/tree-ssa/pr77808.c | 11 +++++++++++
gcc/tree-ssa-loop-prefetch.c | 3 ++-
2 files changed, 13 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr77808.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr77808.c b/gcc/testsuite/gcc.dg/tree-ssa/pr77808.c
new file mode 100644
index 0000000..85393f4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr77808.c
@@ -0,0 +1,11 @@
+/* PR tree-optimization/77808 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fprefetch-loop-arrays --param prefetch-latency=0" } */
+
+void daxpy(int n, double da, double * __restrict dx, double * __restrict dy)
+{
+ int i;
+
+ for (i = 0;i < n; i++)
+ dy[i] = dy[i] + da*dx[i];
+}
diff --git a/gcc/tree-ssa-loop-prefetch.c b/gcc/tree-ssa-loop-prefetch.c
index 056815d..43ee85a 100644
--- a/gcc/tree-ssa-loop-prefetch.c
+++ b/gcc/tree-ssa-loop-prefetch.c
@@ -1162,7 +1162,8 @@ issue_prefetch_ref (struct mem_ref *ref, unsigned unroll_factor, unsigned ahead)
NULL, true, GSI_SAME_STMT);
}
- if (TREE_CODE (addr_base) == SSA_NAME
+ if (addr_base != addr
+ && TREE_CODE (addr_base) == SSA_NAME
&& TREE_CODE (addr) == SSA_NAME)
{
duplicate_ssa_name_ptr_info (addr, SSA_NAME_PTR_INFO (addr_base));
--
1.9.1
