On 12/14/21 17:12, Jakub Jelinek wrote:
I'd use INT_TYPE_SIZE - 1 instead of 31. Otherwise LGTM.
Installed with that change, thanks.
Moreover, I'm suggesting a simplification:
The patch removes unneeded loops for cpu_features2 and CONVERT_EXPR
that can be simplified with NOP_EXPR.
Survives i386.exp tests, may I install the patch after testing or
is it a stage1 material?
Thanks,
Martin
From 9fa89df81b3e6cb56f6ab59b0993168e7a048489 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Wed, 15 Dec 2021 10:54:23 +0100
Subject: [PATCH] i386: simplify cpu_feature handling
The patch removes unneeded loops for cpu_features2 and CONVERT_EXPR
that can be simplified with NOP_EXPR.
gcc/ChangeLog:
* common/config/i386/cpuinfo.h (has_cpu_feature): Directly
compute index in cpu_features2.
(set_cpu_feature): Likewise.
* config/i386/i386-builtins.c (fold_builtin_cpu): Also remove
loop for cpu_features2 and use NOP_EXPRs.
---
gcc/common/config/i386/cpuinfo.h | 50 +++++++++++---------
gcc/config/i386/i386-builtins.c | 79 ++++++++++++++++----------------
2 files changed, 67 insertions(+), 62 deletions(-)
diff --git a/gcc/common/config/i386/cpuinfo.h b/gcc/common/config/i386/cpuinfo.h
index bbf29bdb116..dd321920108 100644
--- a/gcc/common/config/i386/cpuinfo.h
+++ b/gcc/common/config/i386/cpuinfo.h
@@ -55,43 +55,49 @@ struct __processor_model2
static inline int
has_cpu_feature (struct __processor_model *cpu_model,
unsigned int *cpu_features2,
- enum processor_features f)
+ enum processor_features feature)
{
- unsigned int i;
+ unsigned index, offset;
+ unsigned f = feature;
+
if (f < 32)
{
/* The first 32 features. */
- return cpu_model->__cpu_features[0] & (1U << (f & 31));
+ return cpu_model->__cpu_features[0] & (1U << f);
+ }
+ else
+ {
+ /* The rest of features. cpu_features2[i] contains features from
+ (32 + i * 32) to (31 + 32 + i * 32), inclusively. */
+ f -= 32;
+ index = f / 32;
+ offset = f % 32;
+ return cpu_features2[index] & (1U << offset);
}
- /* The rest of features. cpu_features2[i] contains features from
- (32 + i * 32) to (31 + 32 + i * 32), inclusively. */
- for (i = 0; i < SIZE_OF_CPU_FEATURES; i++)
- if (f < (32 + 32 + i * 32))
- return cpu_features2[i] & (1U << ((f - (32 + i * 32)) & 31));
- gcc_unreachable ();
}
static inline void
set_cpu_feature (struct __processor_model *cpu_model,
unsigned int *cpu_features2,
- enum processor_features f)
+ enum processor_features feature)
{
- unsigned int i;
+ unsigned index, offset;
+ unsigned f = feature;
+
if (f < 32)
{
/* The first 32 features. */
- cpu_model->__cpu_features[0] |= (1U << (f & 31));
- return;
+ cpu_model->__cpu_features[0] |= (1U << f);
+ }
+ else
+ {
+ /* The rest of features. cpu_features2[i] contains features from
+ (32 + i * 32) to (31 + 32 + i * 32), inclusively. */
+ f -= 32;
+ index = f / 32;
+ offset = f % 32;
+ cpu_features2[index] |= (1U << offset);
}
- /* The rest of features. cpu_features2[i] contains features from
- (32 + i * 32) to (31 + 32 + i * 32), inclusively. */
- for (i = 0; i < SIZE_OF_CPU_FEATURES; i++)
- if (f < (32 + 32 + i * 32))
- {
- cpu_features2[i] |= (1U << ((f - (32 + i * 32)) & 31));
- return;
- }
- gcc_unreachable ();
}
/* Get the specific type of AMD CPU and return AMD CPU name. Return
diff --git a/gcc/config/i386/i386-builtins.c b/gcc/config/i386/i386-builtins.c
index 4b30cf75c26..31e034e1bc9 100644
--- a/gcc/config/i386/i386-builtins.c
+++ b/gcc/config/i386/i386-builtins.c
@@ -2275,7 +2275,7 @@ fold_builtin_cpu (tree fndecl, tree *args)
/* Check the value. */
final = build2 (EQ_EXPR, unsigned_type_node, ref,
build_int_cstu (unsigned_type_node, field_val));
- return build1 (CONVERT_EXPR, integer_type_node, final);
+ return build1 (NOP_EXPR, integer_type_node, final);
}
else if (fn_code == IX86_BUILTIN_CPU_SUPPORTS)
{
@@ -2300,7 +2300,8 @@ fold_builtin_cpu (tree fndecl, tree *args)
return integer_zero_node;
}
- if (isa_names_table[i].feature >= 32)
+ unsigned feature = isa_names_table[i].feature;
+ if (feature >= INT_TYPE_SIZE)
{
if (ix86_cpu_features2_var == nullptr)
{
@@ -2318,46 +2319,44 @@ fold_builtin_cpu (tree fndecl, tree *args)
varpool_node::add (ix86_cpu_features2_var);
}
- for (unsigned int j = 0; j < SIZE_OF_CPU_FEATURES; j++)
- if (isa_names_table[i].feature < (32 + 32 + j * 32))
- {
- field_val = (1U << (isa_names_table[i].feature
- - (32 + j * 32)));
- tree index = size_int (j);
- array_elt = build4 (ARRAY_REF, unsigned_type_node,
- ix86_cpu_features2_var,
- index, NULL_TREE, NULL_TREE);
- /* Return __cpu_features2[index] & field_val */
- final = build2 (BIT_AND_EXPR, unsigned_type_node,
- array_elt,
- build_int_cstu (unsigned_type_node,
- field_val));
- return build1 (CONVERT_EXPR, integer_type_node, final);
- }
+ feature -= INT_TYPE_SIZE;
+ field_val = 1U << (feature % INT_TYPE_SIZE);
+ tree index = size_int (feature / INT_TYPE_SIZE);
+ array_elt = build4 (ARRAY_REF, unsigned_type_node,
+ ix86_cpu_features2_var,
+ index, NULL_TREE, NULL_TREE);
+ /* Return __cpu_features2[index] & field_val */
+ final = build2 (BIT_AND_EXPR, unsigned_type_node,
+ array_elt,
+ build_int_cstu (unsigned_type_node,
+ field_val));
+ return build1 (NOP_EXPR, integer_type_node, final);
}
-
- field = TYPE_FIELDS (ix86_cpu_model_type_node);
- /* Get the last field, which is __cpu_features. */
- while (DECL_CHAIN (field))
- field = DECL_CHAIN (field);
-
- /* Get the appropriate field: __cpu_model.__cpu_features */
- ref = build3 (COMPONENT_REF, TREE_TYPE (field), ix86_cpu_model_var,
- field, NULL_TREE);
-
- /* Access the 0th element of __cpu_features array. */
- array_elt = build4 (ARRAY_REF, unsigned_type_node, ref,
- integer_zero_node, NULL_TREE, NULL_TREE);
-
- field_val = (1U << isa_names_table[i].feature);
- /* Return __cpu_model.__cpu_features[0] & field_val */
- final = build2 (BIT_AND_EXPR, unsigned_type_node, array_elt,
- build_int_cstu (unsigned_type_node, field_val));
- if (isa_names_table[i].feature == (INT_TYPE_SIZE - 1))
- return build2 (NE_EXPR, integer_type_node, final,
- build_int_cst (unsigned_type_node, 0));
else
- return build1 (CONVERT_EXPR, integer_type_node, final);
+ {
+ field = TYPE_FIELDS (ix86_cpu_model_type_node);
+ /* Get the last field, which is __cpu_features. */
+ while (DECL_CHAIN (field))
+ field = DECL_CHAIN (field);
+
+ /* Get the appropriate field: __cpu_model.__cpu_features */
+ ref = build3 (COMPONENT_REF, TREE_TYPE (field), ix86_cpu_model_var,
+ field, NULL_TREE);
+
+ /* Access the 0th element of __cpu_features array. */
+ array_elt = build4 (ARRAY_REF, unsigned_type_node, ref,
+ integer_zero_node, NULL_TREE, NULL_TREE);
+
+ field_val = (1U << feature);
+ /* Return __cpu_model.__cpu_features[0] & field_val */
+ final = build2 (BIT_AND_EXPR, unsigned_type_node, array_elt,
+ build_int_cstu (unsigned_type_node, field_val));
+ if (feature == (INT_TYPE_SIZE - 1))
+ return build2 (NE_EXPR, integer_type_node, final,
+ build_int_cst (unsigned_type_node, 0));
+ else
+ return build1 (NOP_EXPR, integer_type_node, final);
+ }
}
gcc_unreachable ();
}
--
2.34.1
