https://gcc.gnu.org/g:6683f2cd1ce07fc8470b19dc3c1578b3e0645c25
commit r15-9644-g6683f2cd1ce07fc8470b19dc3c1578b3e0645c25
Author: Eric Botcazou <ebotca...@adacore.com>
Date: Fri May 9 17:45:27 2025 +0200
Fix wrong optimization of complex boolean expression
The VRP2 pass turns:
# prephitmp_3 = PHI <0(4)>
_1 = prephitmp_3 == 0;
_5 = stretch_14(D) ^ 1;
_39 = _1 & _5;
_40 = _39 | last_20(D);
into
_5 = stretch_14(D) ^ 1;
_42 = ~stretch_14(D);
_39 = _42;
_40 = last_20(D) | _39;
using the following step:
Folding statement: _1 = prephitmp_3 == 0;
Queued stmt for removal. Folds to: 1
Folding statement: _5 = stretch_14(D) ^ 1;
Not folded
Folding statement: _39 = _1 & _5;
gimple_simplified to _42 = ~stretch_14(D);
_39 = _42 & 1;
Folded into: _39 = _42;
Folding statement: _40 = _39 | last_20(D);
Folded into: _40 = last_20(D) | _39;
but stretch_14 is a 8-bit boolean so the two forms are not equivalent, that
is to say dropping the "& 1" is wrong. It's another instance of the issue:
https://gcc.gnu.org/pipermail/gcc-patches/2020-November/558537.html
Here it's the reverse case: the bitwise NOT (~) is treated as logical by the
machinery in range-op.cc but the bitwise AND (&) is *not* treated as logical
by that of vr-values.cc, leading to the same problematic outcome.
gcc/
* vr-values.cc (simplify_using_ranges::simplify) <BIT_AND_EXPR>:
Do not call simplify_bit_ops_using_ranges for boolean types whose
precision is not 1.
gcc/testsuite/
* gnat.dg/opt106.adb: New test.
* gnat.dg/opt106_pkg1.ads, gnat.dg/opt106_pkg1.adb: New helper.
* gnat.dg/opt106_pkg2.ads, gnat.dg/opt106_pkg2.adb: Likewise.
Diff:
---
gcc/testsuite/gnat.dg/opt106.adb | 11 ++++++++++
gcc/testsuite/gnat.dg/opt106_pkg1.adb | 39 +++++++++++++++++++++++++++++++++++
gcc/testsuite/gnat.dg/opt106_pkg1.ads | 16 ++++++++++++++
gcc/testsuite/gnat.dg/opt106_pkg2.adb | 11 ++++++++++
gcc/testsuite/gnat.dg/opt106_pkg2.ads | 8 +++++++
gcc/vr-values.cc | 11 ++++++----
6 files changed, 92 insertions(+), 4 deletions(-)
diff --git a/gcc/testsuite/gnat.dg/opt106.adb b/gcc/testsuite/gnat.dg/opt106.adb
new file mode 100644
index 000000000000..525930b47439
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt106.adb
@@ -0,0 +1,11 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+with Opt106_Pkg1; use Opt106_Pkg1;
+
+procedure Opt106 is
+ Obj : T := (False, 0, 0, 0, True);
+
+begin
+ Proc (Obj, 0, False, True);
+end;
diff --git a/gcc/testsuite/gnat.dg/opt106_pkg1.adb
b/gcc/testsuite/gnat.dg/opt106_pkg1.adb
new file mode 100644
index 000000000000..154b13f34ec7
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt106_pkg1.adb
@@ -0,0 +1,39 @@
+with Opt106_Pkg2; use Opt106_Pkg2;
+
+package body Opt106_Pkg1 is
+
+ procedure Proc (Obj : in out T;
+ Data : Integer;
+ Last : Boolean;
+ Stretch : Boolean) is
+
+ begin
+ if Stretch and then (Obj.Delayed /= 0 or else not Obj.Attach_Last) then
+ raise Program_Error;
+ end if;
+
+ if Obj.Delayed /= 0 then
+ Stop (Obj.Delayed, Obj.Before, Data, False);
+ end if;
+
+ if Last or (Obj.Delayed = 0 and not Stretch) then
+ Stop (Data, Obj.Before, 0, Last);
+
+ if Last then
+ Obj.Initialized := False;
+ else
+ Obj.Next := 0;
+ Obj.Before := Data;
+ end if;
+
+ else
+ if Stretch then
+ Obj.Next := 1;
+ else
+ Obj.Before := Obj.Delayed;
+ end if;
+ Obj.Delayed := Data;
+ end if;
+ end;
+
+end Opt106_Pkg1;
diff --git a/gcc/testsuite/gnat.dg/opt106_pkg1.ads
b/gcc/testsuite/gnat.dg/opt106_pkg1.ads
new file mode 100644
index 000000000000..85ac24dc8a95
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt106_pkg1.ads
@@ -0,0 +1,16 @@
+package Opt106_Pkg1 is
+
+ type T is record
+ Initialized : Boolean;
+ Before : Integer;
+ Delayed : Integer;
+ Next : Integer;
+ Attach_Last : Boolean;
+ end record;
+
+ procedure Proc (Obj : in out T;
+ Data : Integer;
+ Last : Boolean;
+ Stretch : Boolean);
+
+end Opt106_Pkg1;
diff --git a/gcc/testsuite/gnat.dg/opt106_pkg2.adb
b/gcc/testsuite/gnat.dg/opt106_pkg2.adb
new file mode 100644
index 000000000000..cf639567fcb7
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt106_pkg2.adb
@@ -0,0 +1,11 @@
+package body Opt106_Pkg2 is
+
+ procedure Stop (Delayed : Integer;
+ Before : Integer;
+ After : Integer;
+ Last : Boolean) is
+ begin
+ raise Program_Error;
+ end;
+
+end Opt106_Pkg2;
diff --git a/gcc/testsuite/gnat.dg/opt106_pkg2.ads
b/gcc/testsuite/gnat.dg/opt106_pkg2.ads
new file mode 100644
index 000000000000..77e5b40da97f
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt106_pkg2.ads
@@ -0,0 +1,8 @@
+package Opt106_Pkg2 is
+
+ procedure Stop (Delayed : Integer;
+ Before : Integer;
+ After : Integer;
+ Last : Boolean);
+
+end Opt106_Pkg2;
diff --git a/gcc/vr-values.cc b/gcc/vr-values.cc
index 6603d90c392c..4c787593b95a 100644
--- a/gcc/vr-values.cc
+++ b/gcc/vr-values.cc
@@ -1996,10 +1996,13 @@ simplify_using_ranges::simplify (gimple_stmt_iterator
*gsi)
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
- /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
- if all the bits being cleared are already cleared or
- all the bits being set are already set. */
- if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR if all the bits
+ being cleared are already cleared or all the bits being set
+ are already set. Beware that boolean types must be handled
+ logically (see range-op.cc) unless they have precision 1. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ && (TREE_CODE (TREE_TYPE (rhs1)) != BOOLEAN_TYPE
+ || TYPE_PRECISION (TREE_TYPE (rhs1)) == 1))
return simplify_bit_ops_using_ranges (gsi, stmt);
break;
