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round: Abolished the CPU rounding mode change and modified it to a different logic. #13435

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Merged
merged 2 commits into from
Mar 8, 2024
Merged

round: Abolished the CPU rounding mode change and modified it to a different logic. #13435

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4aed7e7
Fixed to avoid incorrect optimization with llvm15.0.0
SakiTakamachi Feb 20, 2024
ed08faa
Removed changing CPU round mode and added processing to detect and co…
SakiTakamachi Feb 20, 2024
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18 changes: 13 additions & 5 deletions ext/standard/math.c
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Original file line number Diff line number Diff line change
Expand Up @@ -163,8 +163,7 @@ static inline double php_round_helper(double integral, double value, double expo
* mode. For the specifics of the algorithm, see http://wiki.php.net/rfc/rounding
*/
PHPAPI double _php_math_round(double value, int places, int mode) {
double exponent;
double tmp_value;
double exponent, tmp_value, adjusted_value;
int cpu_round_mode;

if (!zend_finite(value) || value == 0.0) {
Expand All @@ -187,14 +186,23 @@ PHPAPI double _php_math_round(double value, int places, int mode) {
* e.g.
* 0.285 * 10000000000 => 2850000000.0
* floor(0.285 * 10000000000) => 2850000000
*
* Using `if` twice to prevent accidental optimization with llvm 15.0.0.
*/
bool val_is_positive_or_zero = value >= 0.0;
cpu_round_mode = fegetround();
if (value >= 0.0) {
if (val_is_positive_or_zero) {
fesetround(FE_UPWARD);
tmp_value = floor(places > 0 ? value * exponent : value / exponent);
} else {
fesetround(FE_DOWNWARD);
tmp_value = ceil(places > 0 ? value * exponent : value / exponent);
}

adjusted_value = places > 0 ? value * exponent : value / exponent;

if (val_is_positive_or_zero) {
tmp_value = floor(adjusted_value);
} else {
tmp_value = ceil(adjusted_value);
}
fesetround(cpu_round_mode);

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