From a310bb73edc9548e08d1fa28e7a56246caf27757 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Tue, 4 May 2021 10:07:35 +0200
Subject: [PATCH] tree-optimization/100329 - avoid reassociating asm goto defs
This avoids reassociating asm goto defs because we have no idea
on which outgoing edge to insert defs.
2021-05-04 Richard Biener <rguenther@suse.de>
PR tree-optimization/100329
* tree-ssa-reassoc.c (can_reassociate_p): Do not reassociate
asm goto defs.
(insert_stmt_after): Assert we're not running into asm goto.
* gcc.dg/torture/pr100329.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr100329.c | 16 ++++++++++++++++
gcc/tree-ssa-reassoc.c | 10 ++++++++++
2 files changed, 26 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr100329.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr100329.c b/gcc/testsuite/gcc.dg/torture/pr100329.c
new file mode 100644
index 000000000000..b90700dd5f0c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr100329.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "--param tree-reassoc-width=2" } */
+
+unsigned int a0;
+
+unsigned int
+foo (unsigned int a1, unsigned int a2)
+{
+ unsigned int x;
+
+ asm goto ("" : "=r" (x) : : : lab);
+ a0 = x;
+
+ lab:
+ return x + a1 + a2 + 1;
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 8e2a4896d14b..359367c9382c 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -1446,6 +1446,10 @@ insert_stmt_after (gimple *stmt, gimple *insert_point)
gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
return;
}
+ else if (gimple_code (insert_point) == GIMPLE_ASM)
+ /* We have no idea where to insert - it depends on where the
+ uses will be placed. */
+ gcc_unreachable ();
else
/* We assume INSERT_POINT is a SSA_NAME_DEF_STMT of some SSA_NAME,
thus if it must end a basic block, it should be a call that can
@@ -5893,6 +5897,12 @@ can_reassociate_p (tree op)
tree type = TREE_TYPE (op);
if (TREE_CODE (op) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
return false;
+ /* Make sure asm goto outputs do not participate in reassociation since
+ we have no way to find an insertion place after asm goto. */
+ if (TREE_CODE (op) == SSA_NAME
+ && gimple_code (SSA_NAME_DEF_STMT (op)) == GIMPLE_ASM
+ && gimple_asm_nlabels (as_a <gasm *> (SSA_NAME_DEF_STMT (op))) != 0)
+ return false;
if ((ANY_INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_WRAPS (type))
|| NON_SAT_FIXED_POINT_TYPE_P (type)
|| (flag_associative_math && FLOAT_TYPE_P (type)))
--
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