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i386: Do not constrain fmod and remainder patterns with flag_finite_math_only [PR108922]

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According to Intel ISA manual, fprem and fprem1 return NaN when invalid
arithmetic exception is generated. This is documented in Table 8-10 of the
ISA manual and makes these two instructions fully IEEE compatible.

The reverted patch was based on the data from table 3-30 and 3-31 of the
Intel ISA manual, where results in case of st(0) being infinity or
st(1) being 0 are not specified.

2023-02-27  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	PR target/108922
	Revert:
	* config/i386/i386.md (fmodxf3): Enable for flag_finite_math_only only.
	(fmod<mode>3): Ditto.
	(fpremxf4_i387): Ditto.
	(reminderxf3): Ditto.
	(reminder<mode>3): Ditto.
	(fprem1xf4_i387): Ditto.
This commit is contained in:
Uros Bizjak 2023-02-27 22:10:01 +01:00
parent ab76d71179
commit 8020c9c423
1 changed files with 6 additions and 12 deletions
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18
gcc/config/i386/i386.md
View file

@ -19527,8 +19527,7 @@
(set (reg:CCFP FPSR_REG)
(unspec:CCFP [(match_dup 2) (match_dup 3)]
UNSPEC_C2_FLAG))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
"fprem"
[(set_attr "type" "fpspc")
(set_attr "znver1_decode" "vector")
@ -19538,8 +19537,7 @@
[(use (match_operand:XF 0 "register_operand"))
(use (match_operand:XF 1 "general_operand"))
(use (match_operand:XF 2 "general_operand"))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
{
rtx_code_label *label = gen_label_rtx ();
@ -19562,8 +19560,7 @@
[(use (match_operand:MODEF 0 "register_operand"))
(use (match_operand:MODEF 1 "general_operand"))
(use (match_operand:MODEF 2 "general_operand"))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
{
rtx (*gen_truncxf) (rtx, rtx);
@ -19602,8 +19599,7 @@
(set (reg:CCFP FPSR_REG)
(unspec:CCFP [(match_dup 2) (match_dup 3)]
UNSPEC_C2_FLAG))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
"fprem1"
[(set_attr "type" "fpspc")
(set_attr "znver1_decode" "vector")
@ -19613,8 +19609,7 @@
[(use (match_operand:XF 0 "register_operand"))
(use (match_operand:XF 1 "general_operand"))
(use (match_operand:XF 2 "general_operand"))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
{
rtx_code_label *label = gen_label_rtx ();
@ -19637,8 +19632,7 @@
[(use (match_operand:MODEF 0 "register_operand"))
(use (match_operand:MODEF 1 "general_operand"))
(use (match_operand:MODEF 2 "general_operand"))]
"TARGET_USE_FANCY_MATH_387
&& flag_finite_math_only"
"TARGET_USE_FANCY_MATH_387"
{
rtx (*gen_truncxf) (rtx, rtx);