>From bd5541b903747082c984aa92ebe16faeae7b0c71 Mon Sep 17 00:00:00 2001
From: Gwen Fu <[email protected]>
Date: Thu, 27 Mar 2025 15:55:23 +0800
Subject: [PATCH] [Description of 119222 bug] Conversion of inf to integer is
not diagnosed
[How addresses it] In c-warn.cc, function: warnings_for_convert_and_check:
Since the conversion of inf to int occurs when result is FIX_TRUNC_EXPR,
this is the main basis for judgment and processing . Since expr may be a
variable declaration, DECL_INITIAL is required . After that, the program
discusses three situations from the view of floating-point constants,
floating-point expressions,and real-point division expressions to determine
whether it is infinity. The flag bit warn_flag is used to indicate whether
an illegal situation occurs.
[Test cases]
double c = 3.3/4.4-4.4 ;
double b = 1/static_cast<double>(0) ;
int m = b ;
int n = c ;
int f = 1/0 ;
int g = 1/static_cast<double>(0) ;
int h = 1/static_cast<double>(0) / static_cast<double>(0) /
static_cast<double>(0) ;
[Bootstrapping and testing]
host:Ubuntu24 x86_64 (And I think this pathch suitable for any machine
type)
result:
int m = b ; //successful warning
int n = c ; //missing a warning
int f = 1/0;//successful warning
int g =...; int h = ... //successful warning
[Notice]
"int n = c" didn't send a warning ,
"""
REAL_VALUE_TYPE value = TREE_REAL_CST(dst);
bool is_inf = REAL_VALUE_ISINF(value);
"""
And when I execute"call debug_tree(dst)" to clerify the value of c , it
displayed as:
constant -3.6500000000000003552713678800500929355621337890625e+0> .It is
not infinity.
But actually the value mast be infinity
---
gcc/c-family/c-warn.cc | 51 +++++++++++++++++++++++++++++++++---------
1 file changed, 40 insertions(+), 11 deletions(-)
[Changelog]
gcc/c-family/ChangeLog:
* c-warn.cc (conversion_warning):
(warnings_for_convert_and_check):
I use "./contrib/mklog.py *patch " to generate that above . Is this
Changelog?
From bd5541b903747082c984aa92ebe16faeae7b0c71 Mon Sep 17 00:00:00 2001
From: Gwen Fu <[email protected]>
Date: Thu, 27 Mar 2025 15:55:23 +0800
Subject: [PATCH] [Description of 119222 bug] Conversion of inf to integer is
not diagnosed
[How addresses it] In c-warn.cc, function: warnings_for_convert_and_check:
Since the conversion of inf to int occurs when result is FIX_TRUNC_EXPR,
this is the main basis for judgment and processing . Since expr may be a
variable declaration, DECL_INITIAL is required . After that, the program
discusses three situations from the view of floating-point constants,
floating-point expressions,and real-point division expressions to determine
whether it is infinity. The flag bit warn_flag is used to indicate whether
an illegal situation occurs.
[Test cases]
double c = 3.3/4.4-4.4 ;
double b = 1/static_cast<double>(0) ;
int m = b ;
int n = c ;
int f = 1/0 ;
int g = 1/static_cast<double>(0) ;
int h = 1/static_cast<double>(0) / static_cast<double>(0) / static_cast<double>(0) ;
[Bootstrapping and testing]
host:Ubuntu24 x86_64 (And I think this pathch suitable for any machine type)
result:
int m = b ; //successful warning
int n = c ; //missing a warning
int f = 1/0;//successful warning
int g =...; int h = ... //successful warning
[Notice]
"int n = c" didn't send a warning ,
"""
REAL_VALUE_TYPE value = TREE_REAL_CST(dst);
bool is_inf = REAL_VALUE_ISINF(value);
"""
And when I execute"call debug_tree(dst)" to clerify the value of c , it displayed as:
constant -3.6500000000000003552713678800500929355621337890625e+0> .It is not infinity.
But actually the value mast be infinity
---
gcc/c-family/c-warn.cc | 51 +++++++++++++++++++++++++++++++++---------
1 file changed, 40 insertions(+), 11 deletions(-)
[Changelog]
gcc/c-family/ChangeLog:
* c-warn.cc (conversion_warning):
(warnings_for_convert_and_check):
I use "./contrib/mklog.py *patch " to generate that above . Is this Changelog?
diff --git a/gcc/c-family/c-warn.cc b/gcc/c-family/c-warn.cc
index 406b591bfa0..16de902dae8 100644
--- a/gcc/c-family/c-warn.cc
+++ b/gcc/c-family/c-warn.cc
@@ -1283,17 +1283,6 @@ conversion_warning (location_t loc, tree type, tree expr, tree result)
case CEIL_DIV_EXPR:
case EXACT_DIV_EXPR:
case RDIV_EXPR:
- /*Issue a warning about infinity conversion to int*/
- if( TREE_CODE(type) == INTEGER_TYPE
- && TREE_CODE (TREE_OPERAND(expr,1)) == REAL_CST && real_zerop (TREE_OPERAND(expr,1)))
- {
- bool ret = warning_at(loc , OPT_Wfloat_conversion ,
- "conversion from %qT to %qT changes infinity to maximum or minimum integer value",
- expr_type , type) ;
- if(!ret) warning_at(loc , OPT_Wconversion ,
- "conversion from %qT to %qT changes infinity to maximum or minimum integer value",
- expr_type , type) ;
- }
arith_ops = 2;
goto default_;
@@ -1516,6 +1505,46 @@ warnings_for_convert_and_check (location_t loc, tree type, tree expr,
"changes the value of %qE",
exprtype, type, expr);
}
+ /*"inifity to int" this operation belongs to FIX_TRUNC_EXPR*/
+ else if (TREE_CODE(result) == FIX_TRUNC_EXPR
+ && TREE_CODE(exprtype) == REAL_TYPE)
+ {
+ bool warn_flag = false;
+ tree dst = expr;
+ /*Considering that it may be an assignment expression,
+ expr may be a variable declaration.*/
+ if(TREE_CODE(dst) == VAR_DECL)
+ dst = DECL_INITIAL(dst) ;
+
+ if (TREE_CODE(dst) == REAL_CST)
+ {
+ REAL_VALUE_TYPE value = TREE_REAL_CST(dst);
+ bool is_inf = REAL_VALUE_ISINF(value);
+ if (is_inf)
+ warn_flag = true;
+ }
+ else if (TREE_CODE(dst) == RDIV_EXPR
+ && TREE_CODE (TREE_OPERAND(dst, 1)) == REAL_CST
+ && real_zerop (TREE_OPERAND(dst, 1)))
+ warn_flag = true;
+ /*After getting the initial value of the variable,
+ the node type is FLOAT_EXPR*/
+ else if (TREE_CODE(dst) == FLOAT_EXPR
+ && EXPR_P(TREE_OPERAND(dst, 0)))
+ {
+ tree op = TREE_OPERAND(dst, 0) ;
+
+ tree denominator = TREE_OPERAND(op, 1) ;
+ if ((TREE_CODE(denominator) == INTEGER_CST
+ && integer_zerop(denominator)))
+ warn_flag = true;
+ }
+ if(warn_flag)
+ warning_at (loc, 0, "Undefined behavior: conversion "
+ "from %qT to %qT", expr, type);
+
+ conversion_warning(loc , type , expr , result);
+ }
else
conversion_warning (loc, type, expr, result);
}
--
2.45.2
