From: Jakub Jelinek <jakub@redhat.com>
Date: Mon, 16 Mar 2020 08:02:21 +0000 (+0100)
Subject: tree-inline: Fix a -fcompare-debug issue in the inliner [PR94167]
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5ba25b2ef179aec8ba4c47612fbc5c388f41cb36;p=gcc.git

tree-inline: Fix a -fcompare-debug issue in the inliner [PR94167]

The following testcase fails with -fcompare-debug.  The problem is that
bar is marked as address_taken only with -g and not without.
I've tracked it down to insert_init_stmt calling gimple_regimplify_operands
even on DEBUG_STMTs.  That function will just insert normal stmts before
the DEBUG_STMT if the DEBUG_STMT operand isn't gimple val or invariant.
While DCE will turn those statements into debug temporaries, it can cause
differences in SSA_NAMEs and more importantly, the ipa references are
generated from those before the DCE happens.
On the testcase, the DEBUG_STMT value is (int)bar.

We could generate DEBUG_STMTs with debug temporaries instead, but I fail to
see the reason to do that, DEBUG_STMTs allow other expressions and all we
want to ensure is that the expressions aren't too large (arbitrarily
complex), but during inlining/function versioning I don't see why something
would queue a DEBUG_STMT with arbitrarily complex expressions in there.

2020-03-16  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/94166
	* tree-ssa-reassoc.c (sort_by_mach_mode): Use SSA_NAME_VERSION
	as secondary comparison key.

	* gcc.dg/pr94166.c: New test.
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 53c9622afa2..8709f0c7f53 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/94166
+	* tree-ssa-reassoc.c (sort_by_mach_mode): Use SSA_NAME_VERSION
+	as secondary comparison key.
+
 2020-03-16  Bin Cheng  <bin.cheng@linux.alibaba.com>
 
 	PR tree-optimization/94125
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ab0406656d2..d52cd1effa3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/94166
+	* gcc.dg/pr94166.c: New test.
+
 2020-03-16  Bin Cheng  <bin.cheng@linux.alibaba.com>
 
 	PR tree-optimization/94125
diff --git a/gcc/testsuite/gcc.dg/pr94166.c b/gcc/testsuite/gcc.dg/pr94166.c
new file mode 100644
index 00000000000..71917c4a2ec
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94166.c
@@ -0,0 +1,24 @@
+/* PR tree-optimization/94166 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcompare-debug" } */
+
+typedef int __m128i __attribute__((__may_alias__, __vector_size__(4 * sizeof (int))));
+unsigned int b[512];
+
+void
+foo (unsigned int *x, __m128i *y)
+{
+#define A(n) __m128i v##n = y[n];
+#define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7) \
+	     A(n##8) A(n##9) A(n##a) A(n##b) A(n##c) A(n##d) A(n##e) A(n##f)
+#define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7)
+  C(0x)
+#undef A
+#define A(n) *(__m128i *) &b[4 * n] = v##n;
+  C(0x)
+#undef A
+#define A(n) + b[4 * n] + b[4 * n + 1] + b[4 * n + 2] + b[4 * n + 3]
+  *x = *x
+  C(0x)
+  ;
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 359ccaee68d..79871a8c659 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -1793,8 +1793,11 @@ sort_by_mach_mode (const void *p_i, const void *p_j)
     return 1;
   else if (mode1 < mode2)
     return -1;
-  else
-    return 0;
+  if (SSA_NAME_VERSION (tr1) < SSA_NAME_VERSION (tr2))
+    return -1;
+  else if (SSA_NAME_VERSION (tr1) > SSA_NAME_VERSION (tr2))
+    return 1;
+  return 0;
 }
 
 /* Cleanup hash map for VECTOR information.  */