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[Patch PR 45260]: [4.5/4.6 Regression] g++4.5: -prefetch-loop-arrays internal compiler error: in verify_expr, at tree-cfg.c:2541
- From: "Fang, Changpeng" <Changpeng dot Fang at amd dot com>
- To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Cc: "rguenther at suse dot de" <rguenther at suse dot de>, "pinskia at gcc dot gnu dot org" <pinskia at gcc dot gnu dot org>, Zdenek Dvorak <rakdver at kam dot mff dot cuni dot cz>, "sebpop at gmail dot com" <sebpop at gmail dot com>
- Date: Fri, 20 Aug 2010 17:44:00 -0500
- Subject: [Patch PR 45260]: [4.5/4.6 Regression] g++4.5: -prefetch-loop-arrays internal compiler error: in verify_expr, at tree-cfg.c:2541
Hi,
The attached patch fixes PR 45260: [4.5/4.6 Regression] g++4.5: -prefetch-loop-arrays internal compiler error: in verify_expr, at tree-cfg.c:2541
Problem: The prefetch pass generates an ADDR_EXPR for COMPONENT_REF(VIEW_CONVERT_EXPR(SSA_NAME)) whose
address could not be taken, and thus invokes an assertion failure in verify_expr.
Solution: Don't generate prefetch for references whose base address could not be taken.
In this patch, we make may_be_nonaddressable_p (tree expr) global and use it in the prefetch pass.
This patch passed bootstrapping and gcc regression tests on x86_64-unknown-linux-gnu systems ib both
trunk and 4.5 branch.
Is it OK to commit to trunk and 4.5 branch?
Thanks and have a wonderful weekend!
Changpeng
From ac383eec351bab858f0be30b4a89947a566853e2 Mon Sep 17 00:00:00 2001
From: Changpeng Fang <chfang@houghton.(none)>
Date: Fri, 20 Aug 2010 12:10:43 -0700
Subject: [PATCH] pr45260 Don't generate prefetch if the address of base could not be taken.
* tree-flow.h (may_be_nonaddressable_p): New definition. Make the
existing static function global.
*tree-ssa-loop-ivopts.c (may_be_nonaddressable_p): This function
is changed to global.
*tree-ssa-loop-prefetch.c (gather_memory_references_ref): Call
may_be_nonaddressable_p on base, and don't collect this reference
if the address of the base could not be taken.
---
gcc/tree-flow.h | 1 +
gcc/tree-ssa-loop-ivopts.c | 2 +-
gcc/tree-ssa-loop-prefetch.c | 4 ++++
3 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index 04ba532..6731308 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -817,6 +817,7 @@ bool stmt_invariant_in_loop_p (struct loop *, gimple);
bool multiplier_allowed_in_address_p (HOST_WIDE_INT, enum machine_mode,
addr_space_t);
unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode, bool);
+bool may_be_nonaddressable_p (tree expr);
/* In tree-ssa-threadupdate.c. */
extern bool thread_through_all_blocks (bool);
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index a347c86..0029c76 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -1640,7 +1640,7 @@ may_be_unaligned_p (tree ref, tree step)
/* Return true if EXPR may be non-addressable. */
-static bool
+bool
may_be_nonaddressable_p (tree expr)
{
switch (TREE_CODE (expr))
diff --git a/gcc/tree-ssa-loop-prefetch.c b/gcc/tree-ssa-loop-prefetch.c
index 9ad6cd2..4e7068f 100644
--- a/gcc/tree-ssa-loop-prefetch.c
+++ b/gcc/tree-ssa-loop-prefetch.c
@@ -539,6 +539,10 @@ gather_memory_references_ref (struct loop *loop, struct mem_ref_group **refs,
if (step == NULL_TREE)
return false;
+ /* Stop if the address of BASE could not taken. */
+ if (may_be_nonaddressable_p (base))
+ return false;
+
/* Limit non-constant step prefetching only to the innermost loops. */
if (!cst_and_fits_in_hwi (step) && loop->inner != NULL)
return false;
--
1.6.3.3