[backport gcc-4.7/trunk r182545 to fix PR51200 on ARM ] gcc/ 2011-12-20 Bernd Schmidt PR middle-end/51200 * expr.c (store_field): Avoid a direct store if the mode is larger than the size of the bit field. * stor-layout.c (layout_decl): If flag_strict_volatile_bitfields, treat non-volatile bit fields like volatile ones. * toplev.c (process_options): Disallow combination of -fstrict-volatile-bitfields and ABI versions less than 2. * config/arm/arm.c (arm_option_override): Don't enable flag_strict_volatile_bitfields if the ABI version is less than 2. * config/h8300/h8300.c (h8300_option_override): Likewise. * config/rx/rx.c (rx_option_override): Likewise. * config/m32c/m32c.c (m32c_option_override): Likewise. * config/sh/sh.c (sh_option_override): Likewise. gcc/testsuite/ 2011-12-20 Bernd Schmidt PR middle-end/51200 * gcc.target/arm/volatile-bitfields-4.c: New test. * c-c++-common/abi-bf.c: New test. --- gcc-4.6.2/gcc/config/arm/arm.c.~1~ 2011-10-20 11:24:06.000000000 +0200 +++ gcc-4.6.2/gcc/config/arm/arm.c 2011-12-23 14:05:19.000000000 +0100 @@ -2005,7 +2005,8 @@ arm_option_override (void) global_options_set.x_param_values); /* ARM EABI defaults to strict volatile bitfields. */ - if (TARGET_AAPCS_BASED && flag_strict_volatile_bitfields < 0) + if (TARGET_AAPCS_BASED && flag_strict_volatile_bitfields < 0 + && abi_version_at_least(2)) flag_strict_volatile_bitfields = 1; /* Enable sw prefetching at -O3 for CPUS that have prefetch, and we have deemed --- gcc-4.6.2/gcc/config/h8300/h8300.c.~1~ 2010-12-01 14:46:36.000000000 +0100 +++ gcc-4.6.2/gcc/config/h8300/h8300.c 2011-12-23 14:05:19.000000000 +0100 @@ -416,7 +416,7 @@ h8300_option_override (void) } /* This target defaults to strict volatile bitfields. */ - if (flag_strict_volatile_bitfields < 0) + if (flag_strict_volatile_bitfields < 0 && abi_version_at_least(2)) flag_strict_volatile_bitfields = 1; } --- gcc-4.6.2/gcc/config/m32c/m32c.c.~1~ 2011-02-10 20:41:26.000000000 +0100 +++ gcc-4.6.2/gcc/config/m32c/m32c.c 2011-12-23 14:05:19.000000000 +0100 @@ -447,7 +447,7 @@ m32c_option_override (void) flag_ivopts = 0; /* This target defaults to strict volatile bitfields. */ - if (flag_strict_volatile_bitfields < 0) + if (flag_strict_volatile_bitfields < 0 && abi_version_at_least(2)) flag_strict_volatile_bitfields = 1; /* r8c/m16c have no 16-bit indirect call, so thunks are involved. --- gcc-4.6.2/gcc/config/rx/rx.c.~1~ 2011-05-17 10:59:10.000000000 +0200 +++ gcc-4.6.2/gcc/config/rx/rx.c 2011-12-23 14:05:19.000000000 +0100 @@ -2348,7 +2348,7 @@ static void rx_option_override (void) { /* This target defaults to strict volatile bitfields. */ - if (flag_strict_volatile_bitfields < 0) + if (flag_strict_volatile_bitfields < 0 && abi_version_at_least(2)) flag_strict_volatile_bitfields = 1; rx_override_options_after_change (); --- gcc-4.6.2/gcc/config/sh/sh.c.~1~ 2011-06-08 06:07:25.000000000 +0200 +++ gcc-4.6.2/gcc/config/sh/sh.c 2011-12-23 14:05:19.000000000 +0100 @@ -1018,7 +1018,7 @@ sh_option_override (void) sh_fix_range (sh_fixed_range_str); /* This target defaults to strict volatile bitfields. */ - if (flag_strict_volatile_bitfields < 0) + if (flag_strict_volatile_bitfields < 0 && abi_version_at_least(2)) flag_strict_volatile_bitfields = 1; } --- gcc-4.6.2/gcc/expr.c.~1~ 2011-08-10 11:17:32.000000000 +0200 +++ gcc-4.6.2/gcc/expr.c 2011-12-23 14:05:19.000000000 +0100 @@ -5861,6 +5861,8 @@ store_field (rtx target, HOST_WIDE_INT b || bitpos % GET_MODE_ALIGNMENT (mode)) && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (target))) || (bitpos % BITS_PER_UNIT != 0))) + || (bitsize >= 0 && mode != BLKmode + && GET_MODE_BITSIZE (mode) > bitsize) /* If the RHS and field are a constant size and the size of the RHS isn't the same size as the bitfield, we must use bitfield operations. */ --- gcc-4.6.2/gcc/stor-layout.c.~1~ 2011-04-05 16:34:51.000000000 +0200 +++ gcc-4.6.2/gcc/stor-layout.c 2011-12-23 14:05:19.000000000 +0100 @@ -660,12 +660,13 @@ layout_decl (tree decl, unsigned int kno /* See if we can use an ordinary integer mode for a bit-field. Conditions are: a fixed size that is correct for another mode, occupying a complete byte or bytes on proper boundary, - and not volatile or not -fstrict-volatile-bitfields. */ + and not -fstrict-volatile-bitfields. If the latter is set, + we unfortunately can't check TREE_THIS_VOLATILE, as a cast + may make a volatile object later. */ if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT - && !(TREE_THIS_VOLATILE (decl) - && flag_strict_volatile_bitfields > 0)) + && flag_strict_volatile_bitfields <= 0) { enum machine_mode xmode = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1); --- gcc-4.6.2/gcc/testsuite/c-c++-common/abi-bf.c.~1~ 1970-01-01 01:00:00.000000000 +0100 +++ gcc-4.6.2/gcc/testsuite/c-c++-common/abi-bf.c 2011-12-23 14:05:19.000000000 +0100 @@ -0,0 +1,3 @@ +/* { dg-warning "incompatible" } */ +/* { dg-do compile } */ +/* { dg-options "-fstrict-volatile-bitfields -fabi-version=1" } */ --- gcc-4.6.2/gcc/testsuite/gcc.target/arm/volatile-bitfields-4.c.~1~ 1970-01-01 01:00:00.000000000 +0100 +++ gcc-4.6.2/gcc/testsuite/gcc.target/arm/volatile-bitfields-4.c 2011-12-23 14:05:19.000000000 +0100 @@ -0,0 +1,30 @@ +/* { dg-require-effective-target arm_eabi } */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ +/* { dg-final { scan-assembler-times "ldr\[\\t \]+\[^\n\]*,\[\\t \]*\\\[\[^\n\]*\\\]" 2 } } */ +/* { dg-final { scan-assembler-times "str\[\\t \]+\[^\n\]*,\[\\t \]*\\\[\[^\n\]*\\\]" 2 } } */ +/* { dg-final { scan-assembler-not "strb" } } */ + +struct thing { + unsigned a: 8; + unsigned b: 8; + unsigned c: 8; + unsigned d: 8; +}; + +struct thing2 { + volatile unsigned a: 8; + volatile unsigned b: 8; + volatile unsigned c: 8; + volatile unsigned d: 8; +}; + +void test1(volatile struct thing *t) +{ + t->a = 5; +} + +void test2(struct thing2 *t) +{ + t->a = 5; +} --- gcc-4.6.2/gcc/toplev.c.~1~ 2011-02-03 09:29:03.000000000 +0100 +++ gcc-4.6.2/gcc/toplev.c 2011-12-23 14:05:19.000000000 +0100 @@ -1326,6 +1326,13 @@ process_options (void) "and -ftree-loop-linear)"); #endif + if (flag_strict_volatile_bitfields > 0 && !abi_version_at_least (2)) + { + warning (0, "-fstrict-volatile-bitfield disabled; " + "it is incompatible with ABI versions < 2"); + flag_strict_volatile_bitfields = 0; + } + /* Unrolling all loops implies that standard loop unrolling must also be done. */ if (flag_unroll_all_loops)