From fae1b38dc82248b70271f42647fa92b82ca6e200 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Sun, 11 Jul 2004 10:45:39 +0100 Subject: [PATCH] re PR tree-optimization/16437 (New c-torture failures after bitfield patch) PR tree-optimization/16437 * c-common.c (shorten_compare): Don't mark result of conversion to narrower signed type as overflowing. * fold-const.c (decode_field_reference): Determine whether signedness comes from outer type using precision rather than size. testsuite: * gcc.c-torture/execute/bitfld-4.c: New test. From-SVN: r84498 --- gcc/ChangeLog | 8 +++++++ gcc/c-common.c | 7 ++++++- gcc/fold-const.c | 2 +- gcc/testsuite/ChangeLog | 5 +++++ .../gcc.c-torture/execute/bitfld-4.c | 21 +++++++++++++++++++ 5 files changed, 41 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.c-torture/execute/bitfld-4.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b3dec3e1049..efd1f2465e2 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2004-07-11 Joseph S. Myers + + PR tree-optimization/16437 + * c-common.c (shorten_compare): Don't mark result of conversion to + narrower signed type as overflowing. + * fold-const.c (decode_field_reference): Determine whether + signedness comes from outer type using precision rather than size. + 2004-07-11 Phil Edwards * configure.ac: Alphabetize --enable-checking list, add diff --git a/gcc/c-common.c b/gcc/c-common.c index ebb5e65e404..e177d884b2b 100644 --- a/gcc/c-common.c +++ b/gcc/c-common.c @@ -1924,7 +1924,12 @@ shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr, *restype_ptr = c_common_signed_type (*restype_ptr); if (TREE_TYPE (primop1) != *restype_ptr) - primop1 = convert (*restype_ptr, primop1); + { + tree tmp = convert (*restype_ptr, primop1); + TREE_OVERFLOW (tmp) = TREE_OVERFLOW (primop1); + TREE_CONSTANT_OVERFLOW (tmp) = TREE_CONSTANT_OVERFLOW (primop1); + primop1 = tmp; + } if (type != *restype_ptr) { minval = convert (*restype_ptr, minval); diff --git a/gcc/fold-const.c b/gcc/fold-const.c index a1efab1184b..b35dfbf3903 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3296,7 +3296,7 @@ decode_field_reference (tree exp, HOST_WIDE_INT *pbitsize, /* If the number of bits in the reference is the same as the bitsize of the outer type, then the outer type gives the signedness. Otherwise (in case of a small bitfield) the signedness is unchanged. */ - if (outer_type && *pbitsize == tree_low_cst (TYPE_SIZE (outer_type), 1)) + if (outer_type && *pbitsize == TYPE_PRECISION (outer_type)) *punsignedp = TYPE_UNSIGNED (outer_type); /* Compute the mask to access the bitfield. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 99083c291ad..20104dd0da8 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2004-07-11 Joseph S. Myers + + PR tree-optimization/16437 + * gcc.c-torture/execute/bitfld-4.c: New test. + 2004-07-10 Tobias Schlueter * gfortran.fortran-torture/execute/common_2.f90: Add check for diff --git a/gcc/testsuite/gcc.c-torture/execute/bitfld-4.c b/gcc/testsuite/gcc.c-torture/execute/bitfld-4.c new file mode 100644 index 00000000000..6f7d7e25c2f --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/bitfld-4.c @@ -0,0 +1,21 @@ +/* When comparisons of bit-fields to unsigned constants got shortened, + the shortened signed constant was wrongly marked as overflowing, + leading to a later integer_zerop failure and misoptimization. + + Related to bug tree-optimization/16437 but shows the problem on + 32-bit systems. */ +/* Origin: Joseph Myers */ + +extern void abort (void); + +struct s { int a:12, b:20; }; + +struct s x = { -123, -456 }; + +int +main (void) +{ + if (x.a != -123U || x.b != -456U) + abort (); + return 0; +} -- 2.30.2