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Improve performance of PowerPC64 fast_long_add_function

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Detecting overflow with the XER is slow, partially because we have to
clear it before use.

PHP already has a fast way of detecting overflow in its fallback
c implementation. Overflow only occurs if the signs of the two
operands are the same and the sign of the result is different.
Furthermore, leaving it in c allows gcc to schedule the instructions
better.

This is 9% faster on a POWER8 running a simple testcase:

<?php
        function testcase($count = 100000000) {
		$x = 1;
                for ($i = 0; $i < $count; $i++) {
                        $x = $x + 1;
                        $x = $x + 1;
                        $x = $x + 1;
                        $x = $x + 1;
                        $x = $x + 1;
                }
        }

        testcase();
?>
This commit is contained in:
Anton Blanchard 2015-05-26 23:41:42 +10:00 committed by Remi Collet
parent 32e9b744c0
commit fd8fb17be8
1 changed files with 0 additions and 60 deletions
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60
Zend/zend_operators.h
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@ -556,36 +556,6 @@ static zend_always_inline void fast_long_add_function(zval *result, zval *op1, z
"n"(IS_DOUBLE),
"n"(ZVAL_OFFSETOF_TYPE)
: "rax","cc");
#elif defined(__GNUC__) && defined(__powerpc64__)
__asm__(
"ld 14, 0(%1)\n\t"
"ld 15, 0(%2)\n\t"
"li 16, 0 \n\t"
"mtxer 16\n\t"
"addo. 14, 14, 15\n\t"
"bso- 0f\n\t"
"std 14, 0(%0)\n\t"
"li 14, %3\n\t"
"stw 14, %c5(%0)\n\t"
"b 1f\n"
"0:\n\t"
"lfd 0, 0(%1)\n\t"
"lfd 1, 0(%2)\n\t"
"fcfid 0, 0\n\t"
"fcfid 1, 1\n\t"
"fadd 0, 0, 1\n\t"
"li 14, %4\n\t"
"stw 14, %c5(%0)\n\t"
"stfd 0, 0(%0)\n"
"1:"
:
: "r"(&result->value),
"r"(&op1->value),
"r"(&op2->value),
"n"(IS_LONG),
"n"(IS_DOUBLE),
"n"(ZVAL_OFFSETOF_TYPE)
: "r14","r15","r16","fr0","fr1","cc");
#else
/*
* 'result' may alias with op1 or op2, so we need to
@ -680,36 +650,6 @@ static zend_always_inline void fast_long_sub_function(zval *result, zval *op1, z
"n"(IS_DOUBLE),
"n"(ZVAL_OFFSETOF_TYPE)
: "rax","cc");
#elif defined(__GNUC__) && defined(__powerpc64__)
__asm__(
"ld 14, 0(%1)\n\t"
"ld 15, 0(%2)\n\t"
"li 16, 0\n\t"
"mtxer 16\n\t"
"subo. 14, 14, 15\n\t"
"bso- 0f\n\t"
"std 14, 0(%0)\n\t"
"li 14, %3\n\t"
"stw 14, %c5(%0)\n\t"
"b 1f\n"
"0:\n\t"
"lfd 0, 0(%1)\n\t"
"lfd 1, 0(%2)\n\t"
"fcfid 0, 0\n\t"
"fcfid 1, 1\n\t"
"fsub 0, 0, 1\n\t"
"li 14, %4\n\t"
"stw 14, %c5(%0)\n\t"
"stfd 0, 0(%0)\n"
"1:"
:
: "r"(&result->value),
"r"(&op1->value),
"r"(&op2->value),
"n"(IS_LONG),
"n"(IS_DOUBLE),
"n"(ZVAL_OFFSETOF_TYPE)
: "r14","r15","r16","fr0","fr1","cc");
#else
ZVAL_LONG(result, Z_LVAL_P(op1) - Z_LVAL_P(op2));