[PATCH v2] rs6000: Don't use optimize_function_for_speed_p too early [PR108184]

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi,

As Honza pointed out in [1], the current uses of function
optimize_function_for_speed_p in rs6000_option_override_internal
are too early, since the query results from the functions
optimize_function_for_{speed,size}_p could be changed later due
to profile feedback and some function attributes handlings etc.

This patch is to move optimize_function_for_speed_p to all the
use places of the corresponding flags, which follows the existing
practices.  Maybe we can cache it somewhere at an appropriate
timing, but that's another thing.

Comparing with v1[2], this version added one test case for
SAVE_TOC_INDIRECT as Segher questioned and suggested, and it
also considered the possibility of explicit option (see test
cases pr108184-2.c and pr108184-4.c).  I believe that excepting
for the intentional change on optimize_function_for_{speed,
size}_p, there is no other function change.

[1] https://gcc.gnu.org/pipermail/gcc-patches/2022-November/607527.html
[2] https://gcc.gnu.org/pipermail/gcc-patches/2023-January/609379.html

Bootstrapped and regtested on powerpc64-linux-gnu P8,
powerpc64le-linux-gnu P{9,10} and powerpc-ibm-aix.

Is it ok for trunk?

BR,
Kewen
-----
gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_option_override_internal): Remove
	all optimize_function_for_speed_p uses.
	(fusion_gpr_load_p): Call optimize_function_for_speed_p along
	with TARGET_P8_FUSION_SIGN.
	(expand_fusion_gpr_load): Likewise.
	(rs6000_call_aix): Call optimize_function_for_speed_p along with
	TARGET_SAVE_TOC_INDIRECT.
	* config/rs6000/predicates.md (fusion_gpr_mem_load): Call
	optimize_function_for_speed_p along with TARGET_P8_FUSION_SIGN.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr108184-1.c: New test.
	* gcc.target/powerpc/pr108184-2.c: New test.
	* gcc.target/powerpc/pr108184-3.c: New test.
	* gcc.target/powerpc/pr108184-4.c: New test.
---
 gcc/config/rs6000/predicates.md               |  5 +++-
 gcc/config/rs6000/rs6000.cc                   | 19 +++++++++-----
 gcc/testsuite/gcc.target/powerpc/pr108184-1.c | 16 ++++++++++++
 gcc/testsuite/gcc.target/powerpc/pr108184-2.c | 15 +++++++++++
 gcc/testsuite/gcc.target/powerpc/pr108184-3.c | 25 +++++++++++++++++++
 gcc/testsuite/gcc.target/powerpc/pr108184-4.c | 24 ++++++++++++++++++
 6 files changed, 97 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr108184-1.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr108184-2.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr108184-3.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr108184-4.c

diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index a1764018545..9f84468db84 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -1878,7 +1878,10 @@ (define_predicate "fusion_gpr_mem_load"

   /* Handle sign/zero extend.  */
   if (GET_CODE (op) == ZERO_EXTEND
-      || (TARGET_P8_FUSION_SIGN && GET_CODE (op) == SIGN_EXTEND))
+      || (TARGET_P8_FUSION_SIGN
+	  && GET_CODE (op) == SIGN_EXTEND
+	  && (rs6000_isa_flags_explicit & OPTION_MASK_P8_FUSION_SIGN
+	      || optimize_function_for_speed_p (cfun))))
     {
       op = XEXP (op, 0);
       mode = GET_MODE (op);
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 6ac3adcec6b..f47d21980a9 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3997,8 +3997,7 @@ rs6000_option_override_internal (bool global_init_p)
   /* If we can shrink-wrap the TOC register save separately, then use
      -msave-toc-indirect unless explicitly disabled.  */
   if ((rs6000_isa_flags_explicit & OPTION_MASK_SAVE_TOC_INDIRECT) == 0
-      && flag_shrink_wrap_separate
-      && optimize_function_for_speed_p (cfun))
+      && flag_shrink_wrap_separate)
     rs6000_isa_flags |= OPTION_MASK_SAVE_TOC_INDIRECT;

   /* Enable power8 fusion if we are tuning for power8, even if we aren't
@@ -4032,7 +4031,6 @@ rs6000_option_override_internal (bool global_init_p)
      zero extending load, and an explicit sign extension.  */
   if (TARGET_P8_FUSION
       && !(rs6000_isa_flags_explicit & OPTION_MASK_P8_FUSION_SIGN)
-      && optimize_function_for_speed_p (cfun)
       && optimize >= 3)
     rs6000_isa_flags |= OPTION_MASK_P8_FUSION_SIGN;

@@ -25690,7 +25688,10 @@ rs6000_call_aix (rtx value, rtx func_desc, rtx tlsarg, rtx cookie)

 	  /* Can we optimize saving the TOC in the prologue or
 	     do we need to do it at every call?  */
-	  if (TARGET_SAVE_TOC_INDIRECT && !cfun->calls_alloca)
+	  if (TARGET_SAVE_TOC_INDIRECT
+	      && !cfun->calls_alloca
+	      && (rs6000_isa_flags_explicit & OPTION_MASK_SAVE_TOC_INDIRECT
+		  || optimize_function_for_speed_p (cfun)))
 	    cfun->machine->save_toc_in_prologue = true;
 	  else
 	    {
@@ -27557,7 +27558,10 @@ fusion_gpr_load_p (rtx addis_reg,	/* register set via addis.  */

   /* Allow sign/zero extension.  */
   if (GET_CODE (mem) == ZERO_EXTEND
-      || (GET_CODE (mem) == SIGN_EXTEND && TARGET_P8_FUSION_SIGN))
+      || (GET_CODE (mem) == SIGN_EXTEND
+	  && TARGET_P8_FUSION_SIGN
+	  && (rs6000_isa_flags_explicit & OPTION_MASK_P8_FUSION_SIGN
+	      || optimize_function_for_speed_p (cfun))))
     mem = XEXP (mem, 0);

   if (!MEM_P (mem))
@@ -27621,7 +27625,10 @@ expand_fusion_gpr_load (rtx *operands)
   enum rtx_code extend = UNKNOWN;

   if (GET_CODE (orig_mem) == ZERO_EXTEND
-      || (TARGET_P8_FUSION_SIGN && GET_CODE (orig_mem) == SIGN_EXTEND))
+      || (TARGET_P8_FUSION_SIGN
+	  && GET_CODE (orig_mem) == SIGN_EXTEND
+	  && (rs6000_isa_flags_explicit & OPTION_MASK_P8_FUSION_SIGN
+	      || optimize_function_for_speed_p (cfun))))
     {
       extend = GET_CODE (orig_mem);
       orig_mem = XEXP (orig_mem, 0);
diff --git a/gcc/testsuite/gcc.target/powerpc/pr108184-1.c b/gcc/testsuite/gcc.target/powerpc/pr108184-1.c
new file mode 100644
index 00000000000..eae3bb9b7c4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr108184-1.c
@@ -0,0 +1,16 @@
+/* Only possible to fuse sign extended loads with the addis when
+   optimize >= 3 and Power8 fusion takes effects.  -mno-prefixed
+   ensures test point isn't broken (due to prefixed plha).  */
+/* { dg-options "-mdejagnu-tune=power8 -O3 -mno-prefixed" } */
+
+/* Verify it doesn't optimize this function for speed as it's cold,
+   by checking it doesn't try to fuse sign extended loads with addis,
+   which results in a zero extended load and a sign extension.  */
+
+__attribute__ ((cold)) int
+fusion_short (short *p)
+{
+  return p[0x12345];
+}
+
+/* { dg-final { scan-assembler-not {\mextsh\M} } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr108184-2.c b/gcc/testsuite/gcc.target/powerpc/pr108184-2.c
new file mode 100644
index 00000000000..9f703f7fc6b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr108184-2.c
@@ -0,0 +1,15 @@
+/* -mno-prefixed ensures test point isn't broken (due to prefixed plha).  */
+/* { dg-options "-mdejagnu-tune=power8 -O2 -mpower8-fusion-sign -mno-prefixed" } */
+
+/* Verify the explicit option -mpower8-fusion-sign can still fuse
+   sign extended loads with addis, which results in a zero extended
+   load and a sign extension.  It means the cold attribute which
+   indicates to optimize for size doesn't affect.  */
+
+__attribute__ ((cold)) int
+fusion_short (short *p)
+{
+  return p[0x12345];
+}
+
+/* { dg-final { scan-assembler-times {\mextsh\M} 1 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr108184-3.c b/gcc/testsuite/gcc.target/powerpc/pr108184-3.c
new file mode 100644
index 00000000000..ceaa96e4421
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr108184-3.c
@@ -0,0 +1,25 @@
+/* { dg-do compile { target { powerpc*-*-aix* powerpc*-*-linux* } } } */
+/* { dg-require-effective-target fpic } */
+/* { dg-options "-fpic -mno-pcrel -O2" } */
+
+/* Verify it doesn't imply -msave-toc-indirect, so
+   it doesn't take effect and we have two separated
+   toc savings for these two long calls.  */
+
+void foo (void) __attribute__((__longcall__));
+int baz (void) __attribute__((__longcall__));
+
+__attribute__ ((cold)) int
+bar (void)
+{
+  foo ();
+  return baz () + 1;
+}
+
+/* Linux LE */
+/* { dg-final { scan-assembler-times {\mstd 2,24\(1\)} 2 { target powerpc_elfv2 } } } */
+/* Linux BE 64 bit or AIX 64 bit */
+/* { dg-final { scan-assembler-times {\mstd 2,40\(1\)} 2 { target { lp64 && { ! powerpc_elfv2 } } } } } */
+/* AIX 32 bit */
+/* { dg-final { scan-assembler-times {\mstw 2,20\(1\)} 2 { target { ilp32 && powerpc*-*-aix* } } } } */
+
diff --git a/gcc/testsuite/gcc.target/powerpc/pr108184-4.c b/gcc/testsuite/gcc.target/powerpc/pr108184-4.c
new file mode 100644
index 00000000000..2a70a603047
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr108184-4.c
@@ -0,0 +1,24 @@
+/* { dg-do compile { target { powerpc*-*-aix* powerpc*-*-linux* } } } */
+/* { dg-require-effective-target fpic } */
+/* { dg-options "-fpic -mno-pcrel -O2 -msave-toc-indirect" } */
+
+/* Verify the explicit -msave-toc-indirect always
+   takes effect, so there is only one toc saving.  */
+
+void foo (void) __attribute__((__longcall__));
+int baz (void) __attribute__((__longcall__));
+
+__attribute__ ((cold)) int
+bar (void)
+{
+  foo ();
+  return baz () + 1;
+}
+
+/* Linux LE */
+/* { dg-final { scan-assembler-times {\mstd 2,24\(1\)} 1 { target powerpc_elfv2 } } } */
+/* Linux BE 64 bit or AIX 64 bit */
+/* { dg-final { scan-assembler-times {\mstd 2,40\(1\)} 1 { target { lp64 && { ! powerpc_elfv2 } } } } } */
+/* AIX 32 bit */
+/* { dg-final { scan-assembler-times {\mstw 2,20\(1\)} 1 { target { ilp32 && powerpc*-*-aix* } } } } */
+
--
2.37.0