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* [gcc(refs/users/aoliva/heads/testme)] Optimize nonstandard boolean conversions
@ 2022-01-27 9:49 Alexandre Oliva
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Oliva @ 2022-01-27 9:49 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:9ef0e43f0308c518fc4bab7bde9478715dae122e
commit 9ef0e43f0308c518fc4bab7bde9478715dae122e
Author: Alexandre Oliva <oliva@adacore.com>
Date: Wed Dec 29 08:44:56 2021 -0300
Optimize nonstandard boolean conversions
This patch improves the generated code for nonstandard boolean types.
One of the improvements extends the code that avoids converting back
to the nonstandard boolean type an expression computed as standard
boolean, when it will be converted to a(nother) nonstandard boolean
type.
The other improvement involves using the literal representation
constants in an If_Expression instead of dereferencing the T'Val array
when converting to a (nonstandard) boolean type. Avoiding the array
dereference enables the compiler middle-end to propagate the constants
and perform optimizations based on them, to the point of obviating the
improvement above.
Unfortunately, the code generated with this alternate expansion tends
to be slightly larger if it turns out to not enable any further
optimization, though it's most certainly faster, especially on targets
with conditional moves, more so if "store flag" is slow, as on x86.
Still, the array dereference is more straightforward and shorter, so
I've arranged for this alternate expansion to be used only when
optimizing for speed.
[changelog]
* exp_util.adb (Adjust_Result_Type): Leave result in Standard.Boolean
if it's going to be converted to another boolean type.
* exp_ch4.adb (Expand_N_Type_Conversion): When optimizing, convert to
nonstandard booleans with an if_expression with boolean literals.
Diff:
---
gcc/ada/exp_ch4.adb | 37 +++++++++++++++++++++++++++----------
gcc/ada/exp_util.adb | 3 +++
2 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb
index 662f975291e..f9ea2540ed0 100644
--- a/gcc/ada/exp_ch4.adb
+++ b/gcc/ada/exp_ch4.adb
@@ -12760,18 +12760,35 @@ package body Exp_Ch4 is
if not Has_Compatible_Representation (Target_Type, Operand_Type)
and then not Conversion_OK (N)
then
+ if Optimization_Level > 0
+ and then Is_Boolean_Type (Target_Type)
+ then
+ -- Convert x(y) to (if y then x'(True) else x'(False)).
+ -- Use literals, instead of indexing x'val, to enable
+ -- further optimizations in the middle-end.
- -- Convert: x(y) to x'val (ytyp'pos (y))
+ Rewrite (N,
+ Make_If_Expression (Loc,
+ Expressions => New_List (
+ Operand,
+ Convert_To (Target_Type,
+ New_Occurrence_Of (Standard_True, Loc)),
+ Convert_To (Target_Type,
+ New_Occurrence_Of (Standard_False, Loc)))));
- Rewrite (N,
- Make_Attribute_Reference (Loc,
- Prefix => New_Occurrence_Of (Target_Type, Loc),
- Attribute_Name => Name_Val,
- Expressions => New_List (
- Make_Attribute_Reference (Loc,
- Prefix => New_Occurrence_Of (Operand_Type, Loc),
- Attribute_Name => Name_Pos,
- Expressions => New_List (Operand)))));
+ else
+ -- Convert: x(y) to x'val (ytyp'pos (y))
+
+ Rewrite (N,
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (Target_Type, Loc),
+ Attribute_Name => Name_Val,
+ Expressions => New_List (
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (Operand_Type, Loc),
+ Attribute_Name => Name_Pos,
+ Expressions => New_List (Operand)))));
+ end if;
Analyze_And_Resolve (N, Target_Type);
end if;
diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 64324bfcb72..e64929fa4cc 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -424,6 +424,9 @@ package body Exp_Util is
elsif KP in N_Op_Boolean
or else KP in N_Short_Circuit
or else KP = N_Op_Not
+ or else (KP in N_Type_Conversion
+ | N_Unchecked_Type_Conversion
+ and then Is_Boolean_Type (Etype (Parent (N))))
then
return;
^ permalink raw reply [flat|nested] 2+ messages in thread
* [gcc(refs/users/aoliva/heads/testme)] Optimize nonstandard boolean conversions
@ 2022-05-06 7:18 Alexandre Oliva
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Oliva @ 2022-05-06 7:18 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2de5a9685f284dbc7a31a9f6a70a92e03795e205
commit 2de5a9685f284dbc7a31a9f6a70a92e03795e205
Author: Alexandre Oliva <oliva@adacore.com>
Date: Thu Feb 17 03:12:02 2022 -0300
Optimize nonstandard boolean conversions
This patch improves the generated code for nonstandard boolean types.
One of the improvements extends the code that avoids converting back
to the nonstandard boolean type an expression computed as standard
boolean, when it will be converted to a(nother) nonstandard boolean
type.
The other improvement involves using the literal representation
constants in an If_Expression instead of dereferencing the T'Val array
when converting to a (nonstandard) boolean type. Avoiding the array
dereference enables the compiler middle-end to propagate the constants
and perform optimizations based on them, to the point of obviating the
improvement above.
Unfortunately, the code generated with this alternate expansion tends
to be slightly larger if it turns out to not enable any further
optimization, though it's most certainly faster, especially on targets
with conditional moves, more so if "store flag" is slow, as on x86.
Still, the array dereference is more straightforward and shorter, so
I've arranged for this alternate expansion to be used only when
optimizing for speed.
[changelog]
* exp_util.adb (Adjust_Result_Type): Leave result in Standard.Boolean
if it's going to be converted to another boolean type.
* exp_ch4.adb (Expand_N_Type_Conversion): When optimizing, convert to
nonstandard booleans with an if_expression with boolean literals.
Diff:
---
gcc/ada/exp_ch4.adb | 37 +++++++++++++++++++++++++++----------
gcc/ada/exp_util.adb | 3 +++
2 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb
index 08dbd9bd8bf..92ac4226d9c 100644
--- a/gcc/ada/exp_ch4.adb
+++ b/gcc/ada/exp_ch4.adb
@@ -12760,18 +12760,35 @@ package body Exp_Ch4 is
if not Has_Compatible_Representation (Target_Type, Operand_Type)
and then not Conversion_OK (N)
then
+ if Optimization_Level > 0
+ and then Is_Boolean_Type (Target_Type)
+ then
+ -- Convert x(y) to (if y then x'(True) else x'(False)).
+ -- Use literals, instead of indexing x'val, to enable
+ -- further optimizations in the middle-end.
- -- Convert: x(y) to x'val (ytyp'pos (y))
+ Rewrite (N,
+ Make_If_Expression (Loc,
+ Expressions => New_List (
+ Operand,
+ Convert_To (Target_Type,
+ New_Occurrence_Of (Standard_True, Loc)),
+ Convert_To (Target_Type,
+ New_Occurrence_Of (Standard_False, Loc)))));
- Rewrite (N,
- Make_Attribute_Reference (Loc,
- Prefix => New_Occurrence_Of (Target_Type, Loc),
- Attribute_Name => Name_Val,
- Expressions => New_List (
- Make_Attribute_Reference (Loc,
- Prefix => New_Occurrence_Of (Operand_Type, Loc),
- Attribute_Name => Name_Pos,
- Expressions => New_List (Operand)))));
+ else
+ -- Convert: x(y) to x'val (ytyp'pos (y))
+
+ Rewrite (N,
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (Target_Type, Loc),
+ Attribute_Name => Name_Val,
+ Expressions => New_List (
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (Operand_Type, Loc),
+ Attribute_Name => Name_Pos,
+ Expressions => New_List (Operand)))));
+ end if;
Analyze_And_Resolve (N, Target_Type);
end if;
diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 64324bfcb72..e64929fa4cc 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -424,6 +424,9 @@ package body Exp_Util is
elsif KP in N_Op_Boolean
or else KP in N_Short_Circuit
or else KP = N_Op_Not
+ or else (KP in N_Type_Conversion
+ | N_Unchecked_Type_Conversion
+ and then Is_Boolean_Type (Etype (Parent (N))))
then
return;
^ permalink raw reply [flat|nested] 2+ messages in thread
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