diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6763f95db08..28a2c86ef23 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2012-08-02 Richard Henderson + + Revert: + PR 34548 + * function.h (struct rtl_data): Add max_dynamic_stack_alignment. + * cfgexpand.c (gimple_expand_cfg): Initialise it. + * explow.c (allocate_dynamic_stack_space): Set it. Simplify + alignment requirements given the known alignment of dynamic_offset. + * function.c (instantiate_virtual_regs): Align dtnamic_offset. + 2012-08-02 Kenneth Zadeck * cfgexpand.c (expand_debug_locations): Encapsulate test for @@ -389,15 +399,6 @@ * config/mips/mips-tables.opt: Regenerate. * doc/invoke.texi (MIPS Options): Document -march=34kn. -2012-08-01 Richard Henderson - - PR middle-end/34548 - * function.h (struct rtl_data): Add max_dynamic_stack_alignment. - * cfgexpand.c (gimple_expand_cfg): Initialise it. - * explow.c (allocate_dynamic_stack_space): Set it. Simplify - alignment requirements given the known alignment of dynamic_offset. - * function.c (instantiate_virtual_regs): Align dtnamic_offset. - 2012-08-01 Richard Henderson * expmed.h (NUM_MODE_PARTIAL_INT): New. diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c index 00e5e4d99df..e5e26e368a2 100644 --- a/gcc/cfgexpand.c +++ b/gcc/cfgexpand.c @@ -4356,7 +4356,6 @@ gimple_expand_cfg (void) crtl->max_used_stack_slot_alignment = STACK_BOUNDARY; crtl->stack_alignment_estimated = 0; crtl->preferred_stack_boundary = STACK_BOUNDARY; - crtl->max_dynamic_stack_alignment = 0; cfun->cfg->max_jumptable_ents = 0; /* Resovle the function section. Some targets, like ARM EABI rely on knowledge diff --git a/gcc/explow.c b/gcc/explow.c index c7581b06616..1cfe93bc7db 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -1173,6 +1173,7 @@ allocate_dynamic_stack_space (rtx size, unsigned size_align, { HOST_WIDE_INT stack_usage_size = -1; rtx final_label, final_target, target; + unsigned extra_align = 0; bool must_align; /* If we're asking for zero bytes, it doesn't matter what we point @@ -1236,40 +1237,58 @@ allocate_dynamic_stack_space (rtx size, unsigned size_align, else if (size_align < BITS_PER_UNIT) size_align = BITS_PER_UNIT; + /* We can't attempt to minimize alignment necessary, because we don't + know the final value of preferred_stack_boundary yet while executing + this code. */ + if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY) + crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY; + /* We will need to ensure that the address we return is aligned to - REQUIRED_ALIGN. If that alignment is no larger than - PREFERRED_STACK_BOUNDARY, we can handle everything without an - explicit alignment. */ - if (required_align <= PREFERRED_STACK_BOUNDARY) + REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't + always know its final value at this point in the compilation (it + might depend on the size of the outgoing parameter lists, for + example), so we must align the value to be returned in that case. + (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if + STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined). + We must also do an alignment operation on the returned value if + the stack pointer alignment is less strict than REQUIRED_ALIGN. + + If we have to align, we must leave space in SIZE for the hole + that might result from the alignment operation. */ + + must_align = (crtl->preferred_stack_boundary < required_align); + if (must_align) { - if (crtl->preferred_stack_boundary < required_align) - crtl->preferred_stack_boundary = required_align; - if (crtl->max_dynamic_stack_alignment < required_align) - crtl->max_dynamic_stack_alignment = required_align; - must_align = false; + if (required_align > PREFERRED_STACK_BOUNDARY) + extra_align = PREFERRED_STACK_BOUNDARY; + else if (required_align > STACK_BOUNDARY) + extra_align = STACK_BOUNDARY; + else + extra_align = BITS_PER_UNIT; } - else + + /* ??? STACK_POINTER_OFFSET is always defined now. */ +#if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) + must_align = true; + extra_align = BITS_PER_UNIT; +#endif + + if (must_align) { - unsigned extra, extra_align; - - crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY; - crtl->max_dynamic_stack_alignment = PREFERRED_STACK_BOUNDARY; - - extra_align = PREFERRED_STACK_BOUNDARY; - extra = (required_align - extra_align) / BITS_PER_UNIT; + unsigned extra = (required_align - extra_align) / BITS_PER_UNIT; size = plus_constant (Pmode, size, extra); size = force_operand (size, NULL_RTX); if (flag_stack_usage_info) stack_usage_size += extra; + if (extra && size_align > extra_align) size_align = extra_align; - must_align = true; } /* Round the size to a multiple of the required stack alignment. - Since the stack is presumed to be rounded before this allocation, + Since the stack if presumed to be rounded before this allocation, this will maintain the required alignment. If the stack grows downward, we could save an insn by subtracting diff --git a/gcc/function.c b/gcc/function.c index 827f687f421..f1e0b2d3eba 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -1892,14 +1892,7 @@ instantiate_virtual_regs (void) /* Compute the offsets to use for this function. */ in_arg_offset = FIRST_PARM_OFFSET (current_function_decl); var_offset = STARTING_FRAME_OFFSET; - dynamic_offset = STACK_DYNAMIC_OFFSET (current_function_decl); - if (crtl->max_dynamic_stack_alignment) - { - int align = crtl->max_dynamic_stack_alignment / BITS_PER_UNIT; - dynamic_offset = (dynamic_offset + align - 1) & -align; - } - out_arg_offset = STACK_POINTER_OFFSET; #ifdef FRAME_POINTER_CFA_OFFSET cfa_offset = FRAME_POINTER_CFA_OFFSET (current_function_decl); diff --git a/gcc/function.h b/gcc/function.h index ed6fcb198d5..3d3313fc9b3 100644 --- a/gcc/function.h +++ b/gcc/function.h @@ -347,10 +347,6 @@ struct GTY(()) rtl_data { local stack. */ unsigned int stack_alignment_estimated; - /* The (capped) maximum alignment of dynamic stack space, and thus the - required alignment of STACK_DYNAMIC_OFFSET. */ - unsigned int max_dynamic_stack_alignment; - /* For reorg. */ /* If some insns can be deferred to the delay slots of the epilogue, the