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

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

[Uros Bizjak]

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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.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Pushed to master.

Uros.

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diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 8ebb12be2c9..ed689b044c3 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);