On 1/22/20 5:58 PM, Jason Merrill wrote:
On 1/22/20 1:20 PM, Jason Merrill wrote:
On 1/22/20 5:14 AM, Martin Liška wrote:
Hi.
Just for the record, after the change 526.blender_r fails due to:
blender/source/blender/blenlib/intern/math_color.c: In function
'rgb_float_to_uchar':
blender/source/blender/blenlib/BLI_utildefines.h:251:22: error:
conversion from 'float' to 'unsigned char' may change value
[-Werror=float-conversion]
251 | #define FTOCHAR(val) ((CHECK_TYPE_INLINE(val, float)), \
| ^
blender/source/blender/blenlib/BLI_utildefines.h:257:13: note: in
expansion of macro 'FTOCHAR'
257 | (v1)[0] =
FTOCHAR((v2[0])); \
| ^~~~~~~
blender/source/blender/blenlib/intern/math_color.c:421:2: note: in
expansion of macro 'F3TOCHAR3'
421 | F3TOCHAR3(col_f, r_col);
| ^~~~~~~~~
where the project sets -Werror=float-conversion dues to:
$ cat blender/source/blender/blenlib/BLI_strict_flags.h
#ifdef __GNUC__
# if (__GNUC__ * 100 + __GNUC_MINOR__) >= 406 /* gcc4.6+ only */
# pragma GCC diagnostic error "-Wsign-compare"
# pragma GCC diagnostic error "-Wconversion"
# endif
Thanks, investigating.
I wasn't able to reproduce this particular error, but I saw a different
one due to -funsigned-char, fixed thus:
One more tweak, tested powerpc64-linux-gnu.
commit 608199de99de8e4f64e92bdf8b96564d2adeae5e
Author: Jason Merrill <ja...@redhat.com>
Date: Thu Jan 23 10:37:18 2020 -0500
c-family: One more 40752 tweak for unsigned char.
My last patch didn't fix all the failures on unsignd char targets. We were
missing one warning because by suppressing -Wsign-conversion for the second
operand of + we missed an overflow that we want to warn about, and we
properly don't warn about unsigned / or %.
PR testsuite/93391 - PR 40752 test fails with unsigned plain char.
* c-warn.c (conversion_warning): Change -Wsign-conversion handling.
* lib/target-supports.exp (check_effective_target_unsigned_char):
New.
diff --git a/gcc/c-family/c-warn.c b/gcc/c-family/c-warn.c
index 6c73317b4a6..9315cac683e 100644
--- a/gcc/c-family/c-warn.c
+++ b/gcc/c-family/c-warn.c
@@ -1315,10 +1315,14 @@ conversion_warning (location_t loc, tree type, tree expr, tree result)
for (int i = 0; i < arith_ops; ++i)
{
tree op = TREE_OPERAND (expr, i);
- tree opr = convert (type, op);
/* Avoid -Wsign-conversion for (unsigned)(x + (-1)). */
- bool minus = TREE_CODE (expr) == PLUS_EXPR && i == 1;
- if (unsafe_conversion_p (type, op, opr, !minus))
+ if (TREE_CODE (expr) == PLUS_EXPR && i == 1
+ && INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+ && TREE_CODE (op) == INTEGER_CST
+ && tree_int_cst_sgn (op) < 0)
+ op = fold_build1 (NEGATE_EXPR, TREE_TYPE (op), op);
+ tree opr = convert (type, op);
+ if (unsafe_conversion_p (type, op, opr, true))
goto op_unsafe;
}
/* The operands seem safe, we might still want to warn if
diff --git a/gcc/testsuite/c-c++-common/Wconversion-pr40752a.c b/gcc/testsuite/c-c++-common/Wconversion-pr40752a.c
index cd70e34c390..8e3ffae06f6 100644
--- a/gcc/testsuite/c-c++-common/Wconversion-pr40752a.c
+++ b/gcc/testsuite/c-c++-common/Wconversion-pr40752a.c
@@ -14,9 +14,10 @@ void foo(char c, char c2)
c *= 2; /* { dg-warning "conversion" } */
c *= c2; /* { dg-warning "conversion" } */
c /= 2;
- c /= c2; /* { dg-warning "conversion" } */
+ /* If char is unsigned we avoid promoting to int. */
+ c /= c2; /* { dg-warning "conversion" "" { target { ! unsigned_char } } } */
c %= 2;
- c %= c2; /* { dg-warning "conversion" } */
+ c %= c2; /* { dg-warning "conversion" "" { target { ! unsigned_char } } } */
c = -c2; /* { dg-warning "conversion" } */
c = ~c2; /* { dg-warning "conversion" } */
c = c2++;
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index f65a8100da9..3ca3dd3a9e4 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -3115,6 +3115,14 @@ proc check_effective_target_dfprt { } {
}]
}
+# Return 1 iff target has unsigned plain 'char' by default.
+
+proc check_effective_target_unsigned_char {} {
+ return [check_no_compiler_messages unsigned_char assembly {
+ char ar[(char)-1];
+ }]
+}
+
proc check_effective_target_powerpc_popcntb_ok { } {
return [check_cached_effective_target powerpc_popcntb_ok {
