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* [gcc r12-5756] [PR103437] Make backup code for overflow conditional
@ 2021-12-02 17:39 Vladimir Makarov
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From: Vladimir Makarov @ 2021-12-02 17:39 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:cd47cd4b5eb2dfa7a3190e46a3ae93cc87dbe6b1
commit r12-5756-gcd47cd4b5eb2dfa7a3190e46a3ae93cc87dbe6b1
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Thu Dec 2 12:31:28 2021 -0500
[PR103437] Make backup code for overflow conditional
Switch off long long variant overflow code by preprocessor if the
build compiler has __builtin_smul_overflow.
gcc/ChangeLog:
PR rtl-optimization/103437
* ira-color.c (setup_allocno_priorities): Switch off backup code
for overflow if compiler has __builtin_smul_overflow. Use <
for comparison with -INT_MAX.
Diff:
---
gcc/ira-color.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/gcc/ira-color.c b/gcc/ira-color.c
index 3b19a58e1f0..a1b02776e77 100644
--- a/gcc/ira-color.c
+++ b/gcc/ira-color.c
@@ -2797,7 +2797,6 @@ static void
setup_allocno_priorities (ira_allocno_t *consideration_allocnos, int n)
{
int i, length, nrefs, priority, max_priority, mult, diff;
- bool overflow_backup_p = true;
ira_allocno_t a;
max_priority = 0;
@@ -2810,27 +2809,27 @@ setup_allocno_priorities (ira_allocno_t *consideration_allocnos, int n)
ira_assert (mult >= 0);
mult *= ira_reg_class_max_nregs[ALLOCNO_CLASS (a)][ALLOCNO_MODE (a)];
diff = ALLOCNO_MEMORY_COST (a) - ALLOCNO_CLASS_COST (a);
- /* Multiplication can overflow for very large functions.
- Check the overflow and constrain the result if necessary: */
#ifdef __has_builtin
#if __has_builtin(__builtin_smul_overflow)
- overflow_backup_p = false;
+#define HAS_SMUL_OVERFLOW
+#endif
+#endif
+ /* Multiplication can overflow for very large functions.
+ Check the overflow and constrain the result if necessary: */
+#ifdef HAS_SMUL_OVERFLOW
if (__builtin_smul_overflow (mult, diff, &priority)
- || priority <= -INT_MAX)
+ || priority < -INT_MAX)
priority = diff >= 0 ? INT_MAX : -INT_MAX;
+#else
+ static_assert
+ (sizeof (long long) >= 2 * sizeof (int),
+ "overflow code does not work for such int and long long sizes");
+ long long priorityll = (long long) mult * diff;
+ if (priorityll < -INT_MAX || priorityll > INT_MAX)
+ priority = diff >= 0 ? INT_MAX : -INT_MAX;
+ else
+ priority = priorityll;
#endif
-#endif
- if (overflow_backup_p)
- {
- static_assert
- (sizeof (long long) >= 2 * sizeof (int),
- "overflow code does not work for such int and long long sizes");
- long long priorityll = (long long) mult * diff;
- if (priorityll < -INT_MAX || priorityll > INT_MAX)
- priority = diff >= 0 ? INT_MAX : -INT_MAX;
- else
- priority = priorityll;
- }
allocno_priorities[ALLOCNO_NUM (a)] = priority;
if (priority < 0)
priority = -priority;
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