RE: [PATCH] Add attribute hot judgement for INLINE_HINT_known_hot hint.

["Cui, Lili" <lili.cui@intel.com>]

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> Thank you.  Can you please also add a testcase that tests for this.
> So you modify imagemagick marking attribute hot on the specific inline?

Thanks Honza. Added the testcase. I didn't modify source code of 538.imagic_r, the original source code has attribute like:

#define magick_hot_spot  __attribute__((__hot__))
static Cache *SetPixelCacheNexusPixels( ... ) magick_hot_spot;

> I will try to also look again at your earlier patch - I had very busy summer and
> unfortunately lost track on this one.
>
NP, I guessed you were busy during that time, my earlier patch was partially duplicated with function "Elimination_by_inlining_prob", 
except "parameter points to caller local memory" part, maybe we can find a suitable place to add local memory part  to the IPA.

> Honza

gcc/ChangeLog

  * ipa-inline-analysis.cc (do_estimate_edge_time): Add function attribute
  judgement for INLINE_HINT_known_hot hint.

gcc/testsuite/ChangeLog:

  * gcc.dg/ipa/inlinehint-6.c: New test.
---
 gcc/ipa-inline-analysis.cc              | 13 ++++---
 gcc/testsuite/gcc.dg/ipa/inlinehint-6.c | 47 +++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/ipa/inlinehint-6.c

diff --git a/gcc/ipa-inline-analysis.cc b/gcc/ipa-inline-analysis.cc
index 1ca685d1b0e..7bd29c36590 100644
--- a/gcc/ipa-inline-analysis.cc
+++ b/gcc/ipa-inline-analysis.cc
@@ -48,6 +48,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "ipa-utils.h"
 #include "cfgexpand.h"
 #include "gimplify.h"
+#include "attribs.h"
 
 /* Cached node/edge growths.  */
 fast_call_summary<edge_growth_cache_entry *, va_heap> *edge_growth_cache = NULL;
@@ -249,15 +250,19 @@ do_estimate_edge_time (struct cgraph_edge *edge, sreal *ret_nonspec_time)
       hints = estimates.hints;
     }
 
-  /* When we have profile feedback, we can quite safely identify hot
-     edges and for those we disable size limits.  Don't do that when
-     probability that caller will call the callee is low however, since it
+  /* When we have profile feedback or function attribute, we can quite safely
+     identify hot edges and for those we disable size limits.  Don't do that
+     when probability that caller will call the callee is low however, since it
      may hurt optimization of the caller's hot path.  */
-  if (edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
+  if ((edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
       && (edge->count.ipa () * 2
 	  > (edge->caller->inlined_to
 	     ? edge->caller->inlined_to->count.ipa ()
 	     : edge->caller->count.ipa ())))
+      || (lookup_attribute ("hot", DECL_ATTRIBUTES (edge->caller->decl))
+	  != NULL
+	 && lookup_attribute ("hot", DECL_ATTRIBUTES (edge->callee->decl))
+	  != NULL))
     hints |= INLINE_HINT_known_hot;
 
   gcc_checking_assert (size >= 0);
diff --git a/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c b/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c
new file mode 100644
index 00000000000..1f3be641c6d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c
@@ -0,0 +1,47 @@
+/* { dg-options "-O3 -c -fdump-ipa-inline-details -fno-early-inlining -fno-ipa-cp"  } */
+/* { dg-add-options bind_pic_locally } */
+
+#define size_t long long int
+
+struct A
+{
+  size_t f1, f2, f3, f4;
+};
+struct C
+{
+  struct A a;
+  size_t b;
+};
+struct C x;
+
+__attribute__((hot)) struct C callee (struct A *a, struct C *c)
+{
+  c->a=(*a);
+
+  if((c->b + 7) & 17)
+   {
+      c->a.f1 = c->a.f2 + c->a.f1;
+      c->a.f2 = c->a.f3 - c->a.f2;
+      c->a.f3 = c->a.f2 + c->a.f3;
+      c->a.f4 = c->a.f2 - c->a.f4;
+      c->b = c->a.f2;
+
+    }
+  return *c;
+}
+
+__attribute__((hot)) struct C caller (size_t d, size_t e, size_t f, size_t g, struct C *c)
+{
+  struct A a;
+  a.f1 = 1 + d;
+  a.f2 = e;
+  a.f3 = 12 + f;
+  a.f4 = 68 + g;
+  if (c->b > 0)
+    return callee (&a, c);
+  else
+    return *c;
+}
+
+/* { dg-final { scan-ipa-dump "known_hot"  "inline"  } } */
+
-- 
2.17.1

Thanks,
Lili.


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From 8e268572deba097158686eeb10ed45ed33cd2ef5 Mon Sep 17 00:00:00 2001
From: "Cui,Lili" <lili.cui@intel.com>
Date: Wed, 14 Sep 2022 20:08:35 +0800
Subject: [PATCH] Add attribute hot judgement for INLINE_HINT_known_hot hint.

We set up INLINE_HINT_known_hot hint only when we have profile feedback,
now add function attribute judgement for it, when both caller and callee
have __attribute__((hot)), we will also set up INLINE_HINT_known_hot hint
for it.

With this patch applied,
				 Ratio  Code size
ADL Multi-copy:    538.imagic_r  16.7%    1.6%
SPR Multi-copy:    538.imagic_r  15%      1.7%
ICX Multi-copy:    538.imagic_r  15.2%    1.7%
CLX Multi-copy:    538.imagic_r  12.7%    1.7%
Znver3 Multi-copy: 538.imagic_r  10.6%    1.5%

gcc/ChangeLog

  * ipa-inline-analysis.cc (do_estimate_edge_time): Add function attribute
  judgement for INLINE_HINT_known_hot hint.

gcc/testsuite/ChangeLog:

  * gcc.dg/ipa/inlinehint-6.c: New test.
---
 gcc/ipa-inline-analysis.cc              | 13 ++++---
 gcc/testsuite/gcc.dg/ipa/inlinehint-6.c | 47 +++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/ipa/inlinehint-6.c

diff --git a/gcc/ipa-inline-analysis.cc b/gcc/ipa-inline-analysis.cc
index 1ca685d1b0e..7bd29c36590 100644
--- a/gcc/ipa-inline-analysis.cc
+++ b/gcc/ipa-inline-analysis.cc
@@ -48,6 +48,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "ipa-utils.h"
 #include "cfgexpand.h"
 #include "gimplify.h"
+#include "attribs.h"
 
 /* Cached node/edge growths.  */
 fast_call_summary<edge_growth_cache_entry *, va_heap> *edge_growth_cache = NULL;
@@ -249,15 +250,19 @@ do_estimate_edge_time (struct cgraph_edge *edge, sreal *ret_nonspec_time)
       hints = estimates.hints;
     }
 
-  /* When we have profile feedback, we can quite safely identify hot
-     edges and for those we disable size limits.  Don't do that when
-     probability that caller will call the callee is low however, since it
+  /* When we have profile feedback or function attribute, we can quite safely
+     identify hot edges and for those we disable size limits.  Don't do that
+     when probability that caller will call the callee is low however, since it
      may hurt optimization of the caller's hot path.  */
-  if (edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
+  if ((edge->count.ipa ().initialized_p () && edge->maybe_hot_p ()
       && (edge->count.ipa () * 2
 	  > (edge->caller->inlined_to
 	     ? edge->caller->inlined_to->count.ipa ()
 	     : edge->caller->count.ipa ())))
+      || (lookup_attribute ("hot", DECL_ATTRIBUTES (edge->caller->decl))
+	  != NULL
+	 && lookup_attribute ("hot", DECL_ATTRIBUTES (edge->callee->decl))
+	  != NULL))
     hints |= INLINE_HINT_known_hot;
 
   gcc_checking_assert (size >= 0);
diff --git a/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c b/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c
new file mode 100644
index 00000000000..1f3be641c6d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/inlinehint-6.c
@@ -0,0 +1,47 @@
+/* { dg-options "-O3 -c -fdump-ipa-inline-details -fno-early-inlining -fno-ipa-cp"  } */
+/* { dg-add-options bind_pic_locally } */
+
+#define size_t long long int
+
+struct A
+{
+  size_t f1, f2, f3, f4;
+};
+struct C
+{
+  struct A a;
+  size_t b;
+};
+struct C x;
+
+__attribute__((hot)) struct C callee (struct A *a, struct C *c)
+{
+  c->a=(*a);
+
+  if((c->b + 7) & 17)
+   {
+      c->a.f1 = c->a.f2 + c->a.f1;
+      c->a.f2 = c->a.f3 - c->a.f2;
+      c->a.f3 = c->a.f2 + c->a.f3;
+      c->a.f4 = c->a.f2 - c->a.f4;
+      c->b = c->a.f2;
+
+    }
+  return *c;
+}
+
+__attribute__((hot)) struct C caller (size_t d, size_t e, size_t f, size_t g, struct C *c)
+{
+  struct A a;
+  a.f1 = 1 + d;
+  a.f2 = e;
+  a.f3 = 12 + f;
+  a.f4 = 68 + g;
+  if (c->b > 0)
+    return callee (&a, c);
+  else
+    return *c;
+}
+
+/* { dg-final { scan-ipa-dump "known_hot"  "inline"  } } */
+
-- 
2.17.1