From 8020c9c42349f51f75239b9d35a2be41848a97bd Mon Sep 17 00:00:00 2001
From: Uros Bizjak <ubizjak@gmail.com>
Date: Mon, 27 Feb 2023 22:10:01 +0100
Subject: [PATCH] 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.
---
gcc/config/i386/i386.md | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 8ebb12be2c90..ed689b044c34 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -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);
--
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