r10k_safe_mem_expr_p couldn't cope with a MEM_REF of an ADDR_EXPR,
which for some reason is produced for r10k-cache-barrier-8.c when
compiled with -O2 -lto but not when compiled with just -O2.
This function is still much too conservative, but I wanted to be
safe for kernel code that plays clever tricks with link-time symbol
definitions. A trivial example is:
extern char _region_start[];
where _region_start is defined in the linker script.
_region_start[1] can't be seen as an in-range access to an object
as far as the -mr10k-cache-barrier= option is concerned.
Tested on mipsisa64-elf, mips64-elf and mips64-linux-gnu. Applied.
Will be tested once gcc.target/mips uses gcc-dg.
Richard
gcc/
* config/mips/mips.c (r10k_safe_mem_expr_p): Use get_inner_reference.
Index: gcc/config/mips/mips.c
===================================================================
--- gcc/config/mips/mips.c 2012-08-26 11:35:15.000000000 +0100
+++ gcc/config/mips/mips.c 2012-08-26 11:36:43.667807911 +0100
@@ -14446,17 +14446,18 @@ r10k_safe_address_p (rtx x, rtx insn)
static bool
r10k_safe_mem_expr_p (tree expr, HOST_WIDE_INT offset)
{
- if (offset < 0 || offset >= int_size_in_bytes (TREE_TYPE (expr)))
- return false;
+ HOST_WIDE_INT bitoffset, bitsize;
+ tree inner, var_offset;
+ enum machine_mode mode;
+ int unsigned_p, volatile_p;
- while (TREE_CODE (expr) == COMPONENT_REF)
- {
- expr = TREE_OPERAND (expr, 0);
- if (expr == NULL_TREE)
- return false;
- }
+ inner = get_inner_reference (expr, &bitsize, &bitoffset, &var_offset, &mode,
+ &unsigned_p, &volatile_p, false);
+ if (!DECL_P (inner) || !DECL_SIZE_UNIT (inner) || var_offset)
+ return false;
- return DECL_P (expr);
+ offset += bitoffset / BITS_PER_UNIT;
+ return offset >= 0 && offset < tree_low_cst (DECL_SIZE_UNIT (inner), 1);
}
/* A for_each_rtx callback for which DATA points to the instruction
