Re: [PATCH] Read global value/mask in IPA.

[Aldy Hernandez <aldyh@redhat.com>]

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On 7/31/23 18:47, Martin Jambor wrote:
> Hello,
> 
> On Tue, Jul 18 2023, Aldy Hernandez wrote:
>> On 7/17/23 15:14, Aldy Hernandez wrote:
>>> Instead of reading the known zero bits in IPA, read the value/mask
>>> pair which is available.
>>>
>>> There is a slight change of behavior here.  I have removed the check
>>> for SSA_NAME, as the ranger can calculate the range and value/mask for
>>> INTEGER_CST.  This simplifies the code a bit, since there's no special
>>> casing when setting the jfunc bits.  The default range for VR is
>>> undefined, so I think it's safe just to check for undefined_p().
>>
>> Final round of tests revealed a regression for which I've adjusted the
>> testcase.
>>
>> It turns out g++.dg/ipa/pure-const-3.C fails because IPA can now pick up
>> value/mask from any pass that has an integrated ranger.  The test was
>> previously disabling evrp and CCP, but now VRP[12], jump threading, and
>> DOM can make value/mask adjustments visible to IPA so they must be
>> disabled as well.
> 
> So can this be then converted into a new testcase that would test that
> we can now derive something we could not in the past?

Good idea.

This is what I'm testing.  I'm basically testing for "Propagated bits" 
in the ipa-cp pass which is where we are able to propagate more things.

I will commit if it succeeds.

Thanks.
Aldy

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From 57fae00ccccc11070545dd0eacaa5c04547cc553 Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <aldyh@redhat.com>
Date: Fri, 14 Jul 2023 12:38:16 +0200
Subject: [PATCH] Read global value/mask in IPA.

Instead of reading the known zero bits in IPA, read the value/mask
pair which is available.

There is a slight change of behavior here.  I have removed the check
for SSA_NAME, as the ranger can calculate the range and value/mask for
INTEGER_CST.  This simplifies the code a bit, since there's no special
casing when setting the jfunc bits.  The default range for VR is
undefined, so I think it's safe just to check for undefined_p().

gcc/ChangeLog:

	* ipa-prop.cc (ipa_compute_jump_functions_for_edge): Read global
	value/mask.

gcc/testsuite/ChangeLog:

	* g++.dg/ipa/pure-const-3.C: Move source to...
	* g++.dg/ipa/pure-const-3.h: ...here, and adjust original test
	accordingly.
	* g++.dg/ipa/pure-const-3b.C: New.
---
 gcc/ipa-prop.cc                          | 18 ++++++-------
 gcc/testsuite/g++.dg/ipa/pure-const-3.C  | 34 +++---------------------
 gcc/testsuite/g++.dg/ipa/pure-const-3.h  | 29 ++++++++++++++++++++
 gcc/testsuite/g++.dg/ipa/pure-const-3b.C |  6 +++++
 4 files changed, 47 insertions(+), 40 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/ipa/pure-const-3.h
 create mode 100644 gcc/testsuite/g++.dg/ipa/pure-const-3b.C

diff --git a/gcc/ipa-prop.cc b/gcc/ipa-prop.cc
index 5d790ff1265..4f6ed7b89bd 100644
--- a/gcc/ipa-prop.cc
+++ b/gcc/ipa-prop.cc
@@ -2402,8 +2402,7 @@ ipa_compute_jump_functions_for_edge (struct ipa_func_body_info *fbi,
 	}
       else
 	{
-	  if (TREE_CODE (arg) == SSA_NAME
-	      && param_type
+	  if (param_type
 	      && Value_Range::supports_type_p (TREE_TYPE (arg))
 	      && Value_Range::supports_type_p (param_type)
 	      && irange::supports_p (TREE_TYPE (arg))
@@ -2422,15 +2421,14 @@ ipa_compute_jump_functions_for_edge (struct ipa_func_body_info *fbi,
 	    gcc_assert (!jfunc->m_vr);
 	}
 
-      if (INTEGRAL_TYPE_P (TREE_TYPE (arg))
-	  && (TREE_CODE (arg) == SSA_NAME || TREE_CODE (arg) == INTEGER_CST))
+      if (INTEGRAL_TYPE_P (TREE_TYPE (arg)) && !vr.undefined_p ())
 	{
-	  if (TREE_CODE (arg) == SSA_NAME)
-	    ipa_set_jfunc_bits (jfunc, 0,
-				widest_int::from (get_nonzero_bits (arg),
-						  TYPE_SIGN (TREE_TYPE (arg))));
-	  else
-	    ipa_set_jfunc_bits (jfunc, wi::to_widest (arg), 0);
+	  irange &r = as_a <irange> (vr);
+	  irange_bitmask bm = r.get_bitmask ();
+	  signop sign = TYPE_SIGN (TREE_TYPE (arg));
+	  ipa_set_jfunc_bits (jfunc,
+			      widest_int::from (bm.value (), sign),
+			      widest_int::from (bm.mask (), sign));
 	}
       else if (POINTER_TYPE_P (TREE_TYPE (arg)))
 	{
diff --git a/gcc/testsuite/g++.dg/ipa/pure-const-3.C b/gcc/testsuite/g++.dg/ipa/pure-const-3.C
index b4a4673e86e..62d355b4ce7 100644
--- a/gcc/testsuite/g++.dg/ipa/pure-const-3.C
+++ b/gcc/testsuite/g++.dg/ipa/pure-const-3.C
@@ -1,32 +1,6 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fno-ipa-vrp -fdump-tree-optimized -fno-tree-ccp -fdisable-tree-evrp"  } */
-int *ptr;
-static int barvar;
-static int b(int a);
-/* We can not detect A to be const because it may be interposed by unoptimized
-   body.  */
-inline
-__attribute__ ((noinline))
-int a(int a)
-{
-  if (a>0)
-    return b(a-1);
-  return *ptr == *ptr;
-}
-inline
-__attribute__ ((noinline))
-static int b(int p)
-{
-  if (p<0)
-    return a(p+1);
-  return 1;
-}
-int main()
-{
-  int aa;
-  ptr = &barvar;
-  aa=!b(3);
-  ptr = 0;
-  return aa;
-}
+/* { dg-options "-O2 -fno-ipa-vrp -fdump-tree-optimized -fno-tree-ccp -fdisable-tree-evrp -fdisable-tree-vrp1 -fdisable-tree-vrp2 -fno-thread-jumps -fno-tree-dominator-opts"  } */
+
+#include "pure-const-3.h"
+
 /* { dg-final { scan-tree-dump "barvar"  "optimized"  } } */
diff --git a/gcc/testsuite/g++.dg/ipa/pure-const-3.h b/gcc/testsuite/g++.dg/ipa/pure-const-3.h
new file mode 100644
index 00000000000..61d162f541e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ipa/pure-const-3.h
@@ -0,0 +1,29 @@
+int *ptr;
+static int barvar;
+static int b(int a);
+/* We can not detect A to be const because it may be interposed by unoptimized
+   body.  */
+inline
+__attribute__ ((noinline))
+int a(int a)
+{
+  if (a>0)
+    return b(a-1);
+  return *ptr == *ptr;
+}
+inline
+__attribute__ ((noinline))
+static int b(int p)
+{
+  if (p<0)
+    return a(p+1);
+  return 1;
+}
+int main()
+{
+  int aa;
+  ptr = &barvar;
+  aa=!b(3);
+  ptr = 0;
+  return aa;
+}
diff --git a/gcc/testsuite/g++.dg/ipa/pure-const-3b.C b/gcc/testsuite/g++.dg/ipa/pure-const-3b.C
new file mode 100644
index 00000000000..eaa48429b4e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ipa/pure-const-3b.C
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-ipa-vrp -fno-tree-ccp -fdisable-tree-evrp -fno-thread-jumps -fdump-ipa-cp-details" } */
+
+#include "pure-const-3.h"
+
+/* { dg-final { scan-ipa-dump "Propagated bits info for function int b"  "cp"  } } */
-- 
2.41.0