diff options
| -rw-r--r-- | gcc/c-family/c-warn.c | 28 | ||||
| -rw-r--r-- | gcc/testsuite/c-c++-common/pr101537.c | 26 | ||||
| -rw-r--r-- | gcc/testsuite/c-c++-common/pr103881.c | 20 |
3 files changed, 74 insertions, 0 deletions
diff --git a/gcc/c-family/c-warn.c b/gcc/c-family/c-warn.c index 005c9ac..1ce2202 100644 --- a/gcc/c-family/c-warn.c +++ b/gcc/c-family/c-warn.c @@ -1304,6 +1304,34 @@ conversion_warning (location_t loc, tree type, tree expr, tree result) || conversion_warning (loc, type, op2, result)); } + case BIT_AND_EXPR: + if (TREE_CODE (expr_type) == INTEGER_TYPE + && TREE_CODE (type) == INTEGER_TYPE) + for (int i = 0; i < 2; ++i) + { + tree op = TREE_OPERAND (expr, i); + if (TREE_CODE (op) != INTEGER_CST) + continue; + + /* If one of the operands is a non-negative constant + that fits in the target type, then the type of the + other operand does not matter. */ + if (int_fits_type_p (op, c_common_signed_type (type)) + && int_fits_type_p (op, c_common_unsigned_type (type))) + return false; + + /* If constant is unsigned and fits in the target + type, then the result will also fit. */ + if (TYPE_UNSIGNED (TREE_TYPE (op)) && int_fits_type_p (op, type)) + return false; + } + /* FALLTHRU */ + case BIT_IOR_EXPR: + case BIT_XOR_EXPR: + return (conversion_warning (loc, type, TREE_OPERAND (expr, 0), result) + || conversion_warning (loc, type, TREE_OPERAND (expr, 1), + result)); + default_: default: conversion_kind = unsafe_conversion_p (type, expr, result, true); diff --git a/gcc/testsuite/c-c++-common/pr101537.c b/gcc/testsuite/c-c++-common/pr101537.c new file mode 100644 index 0000000..c0c3cfc --- /dev/null +++ b/gcc/testsuite/c-c++-common/pr101537.c @@ -0,0 +1,26 @@ +/* PR c/101537 */ +/* { dg-do compile } */ +/* { dg-options "-Wconversion" } */ + +int +foo () +{ + int aaa = 1; + unsigned char bbb = 0; + bbb |= aaa ? 1 : 0; + return bbb; +} + +int +bar (unsigned char x, int f) +{ + x |= f ? 1 : 0; + return x; +} + +int +baz (unsigned char x, int f) +{ + x = x | f ? 1 : 0; + return x; +} diff --git a/gcc/testsuite/c-c++-common/pr103881.c b/gcc/testsuite/c-c++-common/pr103881.c new file mode 100644 index 0000000..bb3f53b --- /dev/null +++ b/gcc/testsuite/c-c++-common/pr103881.c @@ -0,0 +1,20 @@ +/* PR c/103881 */ +/* { dg-do compile } */ +/* { dg-options "-Wconversion" } */ + +unsigned char bar (void); + +void +foo (void) +{ + unsigned char t = 0; + t |= bar (); + t |= bar () & bar (); /* { dg-bogus "conversion from 'int' to 'unsigned char' may change value" "" { xfail c++ } } */ + t &= bar () & bar (); /* { dg-bogus "conversion from 'int' to 'unsigned char' may change value" "" { xfail c++ } } */ + t = bar () & bar (); + + unsigned char a = bar (); + t |= a & a; + t |= bar () & a; /* { dg-bogus "conversion from 'int' to 'unsigned char' may change value" "" { xfail c++ } } */ + t |= a & bar (); /* { dg-bogus "conversion from 'int' to 'unsigned char' may change value" "" { xfail c++ } } */ +} |