Warn when coercing NAN to other types #19573
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arnaud-lb
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Aug 29, 2025
| @@ -7728,7 +7728,14 @@ static int zend_jit_bool_jmpznz(zend_jit_ctx *jit, const zend_op *opline, uint32 | |||
| if_double = ir_IF(ir_EQ(type, ir_CONST_U8(IS_DOUBLE))); | |||
| ir_IF_TRUE(if_double); | |||
| } | |||
| ref = ir_NE(jit_Z_DVAL(jit, op1_addr), ir_CONST_DOUBLE(0.0)); | |||
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Need to avoid calling zend_is_true() during compilation above when the value is a const nan, otherwise we emit two warnings here: (during tracing, then while compiling the trace)
echo (bool)NAN;There was a problem hiding this comment.
I've done a check, but now the function JIT doesn't emit a warning :/
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| * Those optimizations are not safe if the other operand end up being NAN | ||
| * as BOOL/BOOL_NOT will warn which IS_EQUAL/IS_NOT_EQUAL do not. |
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Triggered a benchmark to check the effect of this: valgrind shows no regression (changes are under 0.0x%).
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I do wonder if this is not actually a problem for switch cases too now that I think of.
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Yeah, it seems I completely broke switch statements...
<?php
$nan = fdiv(0, 0);
switch ($nan) {
case true:
echo "true";
break;
case false:
echo "false";
break;
}
?>Returns nothing now, even without opcache :|
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| if (Z_MODE(op1_addr) == IS_CONST_ZVAL) { | ||
| if (zend_is_true(Z_ZV(op1_addr))) { | ||
| zval *op1 = Z_ZV(op1_addr); | ||
| /* NAN Value must cause a warning to be emitted */ | ||
| // TODO function JIT does not emit warning | ||
| if ((Z_TYPE_P(op1) == IS_DOUBLE && zend_isnan(Z_DVAL_P(op1))) || zend_is_true(op1)) { | ||
| always_true = 1; |
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That's because the cast gets optimized to a constant true when setting always_true = 1. You need to skip the if (Z_MODE(op1_addr) == IS_CONST_ZVAL) { branch entirely when it's nan.
| @@ -16,6 +16,7 @@ | |||
| * +----------------------------------------------------------------------+ | |||
| */ | |||
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| #include "../../../Zend/zend_types.h" | |||
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Suggested change
| #include "../../../Zend/zend_types.h" | |
| #include "Zend/zend_types.h" |
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| * Those optimizations are not safe if the other operand end up being NAN | ||
| * as BOOL/BOOL_NOT will warn which IS_EQUAL/IS_NOT_EQUAL do not. |
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RFC: https://wiki.php.net/rfc/warnings-php-8-5#coercing_nan_to_other_types