From: Tamar Christina <tamar.christina@arm.com>
To: gcc-patches@gcc.gnu.org
Cc: nd@arm.com, rguenther@suse.de, jlaw@ventanamicro.com
Subject: [PATCH 1/2]middle-end: fix wide_int_constant_multiple_p when VAL and DIV are 0. [PR114932]
Date: Mon, 1 Jul 2024 21:13:43 +0100 [thread overview]
Message-ID: <patch-18602-tamar@arm.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1782 bytes --]
Hi All,
wide_int_constant_multiple_p tries to check if for two tree expressions a and b
that there is a multiplier which makes a == b * c.
This code however seems to think that there's no c where a=0 and b=0 are equal
which is of course wrong.
This fixes it and also fixes the comment.
Bootstrapped Regtested on aarch64-none-linux-gnu,
x86_64-pc-linux-gnu -m32, -m64 and no issues.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
PR tree-optimization/114932
* tree-affine.cc (wide_int_constant_multiple_p): Support 0 and 0 being
multiples.
---
diff --git a/gcc/tree-affine.cc b/gcc/tree-affine.cc
index d6309c4390362b680f0aa97a41fac3281ade66fd..bfea0fe826a6affa0ace154e3ca38c9ef632fcba 100644
--- a/gcc/tree-affine.cc
+++ b/gcc/tree-affine.cc
@@ -880,11 +880,10 @@ free_affine_expand_cache (hash_map<tree, name_expansion *> **cache)
*cache = NULL;
}
-/* If VAL != CST * DIV for any constant CST, returns false.
- Otherwise, if *MULT_SET is true, additionally compares CST and MULT,
- and if they are different, returns false. Finally, if neither of these
- two cases occur, true is returned, and CST is stored to MULT and MULT_SET
- is set to true. */
+/* If VAL == CST * DIV for any constant CST, returns true.
+ and if *MULT_SET is true, additionally compares CST and MULT
+ and if they are different, returns false. If true is returned, CST is
+ stored to MULT and MULT_SET is set to true. */
static bool
wide_int_constant_multiple_p (const poly_widest_int &val,
@@ -895,6 +894,12 @@ wide_int_constant_multiple_p (const poly_widest_int &val,
if (known_eq (val, 0))
{
+ if (maybe_eq (div, 0))
+ {
+ *mult = 1;
+ return true;
+ }
+
if (*mult_set && maybe_ne (*mult, 0))
return false;
*mult_set = true;
--
[-- Attachment #2: rb18602.patch --]
[-- Type: text/x-diff, Size: 1225 bytes --]
diff --git a/gcc/tree-affine.cc b/gcc/tree-affine.cc
index d6309c4390362b680f0aa97a41fac3281ade66fd..bfea0fe826a6affa0ace154e3ca38c9ef632fcba 100644
--- a/gcc/tree-affine.cc
+++ b/gcc/tree-affine.cc
@@ -880,11 +880,10 @@ free_affine_expand_cache (hash_map<tree, name_expansion *> **cache)
*cache = NULL;
}
-/* If VAL != CST * DIV for any constant CST, returns false.
- Otherwise, if *MULT_SET is true, additionally compares CST and MULT,
- and if they are different, returns false. Finally, if neither of these
- two cases occur, true is returned, and CST is stored to MULT and MULT_SET
- is set to true. */
+/* If VAL == CST * DIV for any constant CST, returns true.
+ and if *MULT_SET is true, additionally compares CST and MULT
+ and if they are different, returns false. If true is returned, CST is
+ stored to MULT and MULT_SET is set to true. */
static bool
wide_int_constant_multiple_p (const poly_widest_int &val,
@@ -895,6 +894,12 @@ wide_int_constant_multiple_p (const poly_widest_int &val,
if (known_eq (val, 0))
{
+ if (maybe_eq (div, 0))
+ {
+ *mult = 1;
+ return true;
+ }
+
if (*mult_set && maybe_ne (*mult, 0))
return false;
*mult_set = true;
next reply other threads:[~2024-07-01 20:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-01 20:13 Tamar Christina [this message]
2024-07-01 20:14 ` [PATCH 2/2]middle-end: replace constant_multiple_of with aff_combination_constant_multiple_p [PR114932] Tamar Christina
2024-07-02 7:58 ` Richard Biener
2024-07-01 20:32 ` [PATCH 1/2]middle-end: fix wide_int_constant_multiple_p when VAL and DIV are 0. [PR114932] Tamar Christina
2024-07-02 8:01 ` Richard Biener
2024-07-02 9:46 ` Alex Coplan
2024-07-02 10:17 ` Alex Coplan
2024-07-02 11:41 ` Richard Biener
2024-07-02 13:36 ` Alex Coplan
2024-07-02 20:00 ` Richard Sandiford
2024-07-02 7:56 ` Richard Biener
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