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.
We've run into these scenarios multiple times in the past-- any
improvements to the ranger pipeline causes everyone to get smarter,
making changes visible earlier in the pipeline.
Aldy
From e1dfd4d6b3d3bf09d55b6ea3ac732462c7030802 Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <al...@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: Adjust for smarter value/mask being
read by ranger earlier than expected by test.
---
gcc/ipa-prop.cc | 18 ++++++++----------
gcc/testsuite/g++.dg/ipa/pure-const-3.C | 2 +-
2 files changed, 9 insertions(+), 11 deletions(-)
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..e43cf09af27 100644
--- a/gcc/testsuite/g++.dg/ipa/pure-const-3.C
+++ b/gcc/testsuite/g++.dg/ipa/pure-const-3.C
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fno-ipa-vrp -fdump-tree-optimized -fno-tree-ccp -fdisable-tree-evrp" } */
+/* { 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" } */
int *ptr;
static int barvar;
static int b(int a);
--
2.40.1
