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re PR rtl-optimization/66152 (suboptimal load bytes to stack)

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PR rtl-optimization/66152
	* builtins.h (c_readstr): Declare.
	* builtins.c (c_readstr): Remove forward declaration.  Add
	null_terminated_p argument, if false, read all bytes from the
	string instead of stopping after '\0'.
	* expr.c (string_cst_read_str): New function.
	(store_expr): Use string_cst_read_str instead of
	builtin_strncpy_read_str.  Try to store by pieces the whole
	exp_len first, and only if that fails, split it up into
	store by pieces followed by clear_storage.  Formatting fix.

	* gcc.target/i386/pr66152.c: New test.

From-SVN: r268957
This commit is contained in:
Jakub Jelinek 2019-02-16 12:20:33 +01:00 committed by Jakub Jelinek
parent 1f1d52e33d
commit 3140b2ed03
6 changed files with 92 additions and 27 deletions
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11
gcc/ChangeLog
View File

@ -1,5 +1,16 @@
2019-02-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/66152
* builtins.h (c_readstr): Declare.
* builtins.c (c_readstr): Remove forward declaration. Add
null_terminated_p argument, if false, read all bytes from the
string instead of stopping after '\0'.
* expr.c (string_cst_read_str): New function.
(store_expr): Use string_cst_read_str instead of
builtin_strncpy_read_str. Try to store by pieces the whole
exp_len first, and only if that fails, split it up into
store by pieces followed by clear_storage. Formatting fix.
* config/i386/i386.md (*movqi_internal): Remove static from
buf variable. Use output_asm_insn (buf, operands); return "";
instead of return buf;.

13
gcc/builtins.c
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@ -95,7 +95,6 @@ builtin_info_type builtin_info[(int)END_BUILTINS];
/* Non-zero if __builtin_constant_p should be folded right away. */
bool force_folding_builtin_constant_p;
static rtx c_readstr (const char *, scalar_int_mode);
static int target_char_cast (tree, char *);
static rtx get_memory_rtx (tree, tree);
static int apply_args_size (void);
@ -802,10 +801,14 @@ c_strlen (tree src, int only_value, c_strlen_data *data, unsigned eltsize)
}
/* Return a constant integer corresponding to target reading
GET_MODE_BITSIZE (MODE) bits from string constant STR. */
GET_MODE_BITSIZE (MODE) bits from string constant STR. If
NULL_TERMINATED_P, reading stops after '\0' character, all further ones
are assumed to be zero, otherwise it reads as many characters
as needed. */
static rtx
c_readstr (const char *str, scalar_int_mode mode)
rtx
c_readstr (const char *str, scalar_int_mode mode,
bool null_terminated_p/*=true*/)
{
HOST_WIDE_INT ch;
unsigned int i, j;
@ -830,7 +833,7 @@ c_readstr (const char *str, scalar_int_mode mode)
j = j + UNITS_PER_WORD - 2 * (j % UNITS_PER_WORD) - 1;
j *= BITS_PER_UNIT;
if (ch)
if (ch || !null_terminated_p)
ch = (unsigned char) str[i];
tmp[j / HOST_BITS_PER_WIDE_INT] |= ch << (j % HOST_BITS_PER_WIDE_INT);
}

1
gcc/builtins.h
View File

@ -103,6 +103,7 @@ struct c_strlen_data
};
extern tree c_strlen (tree, int, c_strlen_data * = NULL, unsigned = 1);
extern rtx c_readstr (const char *, scalar_int_mode, bool = true);
extern void expand_builtin_setjmp_setup (rtx, rtx);
extern void expand_builtin_setjmp_receiver (rtx);
extern void expand_builtin_update_setjmp_buf (rtx);

64
gcc/expr.c
View File

@ -5453,6 +5453,30 @@ emit_storent_insn (rtx to, rtx from)
return maybe_expand_insn (code, 2, ops);
}
/* Helper function for store_expr storing of STRING_CST. */
static rtx
string_cst_read_str (void *data, HOST_WIDE_INT offset, scalar_int_mode mode)
{
tree str = (tree) data;
gcc_assert (offset >= 0);
if (offset >= TREE_STRING_LENGTH (str))
return const0_rtx;
if ((unsigned HOST_WIDE_INT) offset + GET_MODE_SIZE (mode)
> (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (str))
{
char *p = XALLOCAVEC (char, GET_MODE_SIZE (mode));
size_t l = TREE_STRING_LENGTH (str) - offset;
memcpy (p, TREE_STRING_POINTER (str) + offset, l);
memset (p + l, '\0', GET_MODE_SIZE (mode) - l);
return c_readstr (p, mode, false);
}
return c_readstr (TREE_STRING_POINTER (str) + offset, mode, false);
}
/* Generate code for computing expression EXP,
and storing the value into TARGET.
@ -5472,7 +5496,7 @@ emit_storent_insn (rtx to, rtx from)
rtx
store_expr (tree exp, rtx target, int call_param_p,
bool nontemporal, bool reverse)
bool nontemporal, bool reverse)
{
rtx temp;
rtx alt_rtl = NULL_RTX;
@ -5606,36 +5630,32 @@ store_expr (tree exp, rtx target, int call_param_p,
if (TREE_STRING_LENGTH (str) <= 0)
goto normal_expr;
str_copy_len = strlen (TREE_STRING_POINTER (str));
if (str_copy_len < TREE_STRING_LENGTH (str) - 1)
goto normal_expr;
if (can_store_by_pieces (exp_len, string_cst_read_str, (void *) str,
MEM_ALIGN (target), false))
{
store_by_pieces (target, exp_len, string_cst_read_str, (void *) str,
MEM_ALIGN (target), false, RETURN_BEGIN);
return NULL_RTX;
}
str_copy_len = TREE_STRING_LENGTH (str);
if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0
&& TREE_STRING_POINTER (str)[TREE_STRING_LENGTH (str) - 1] == '\0')
if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0)
{
str_copy_len += STORE_MAX_PIECES - 1;
str_copy_len &= ~(STORE_MAX_PIECES - 1);
}
str_copy_len = MIN (str_copy_len, exp_len);
if (!can_store_by_pieces (str_copy_len, builtin_strncpy_read_str,
CONST_CAST (char *, TREE_STRING_POINTER (str)),
MEM_ALIGN (target), false))
if (str_copy_len >= exp_len)
goto normal_expr;
dest_mem = target;
if (!can_store_by_pieces (str_copy_len, string_cst_read_str,
(void *) str, MEM_ALIGN (target), false))
goto normal_expr;
memop_ret retmode = exp_len > str_copy_len ? RETURN_END : RETURN_BEGIN;
dest_mem = store_by_pieces (dest_mem,
str_copy_len, builtin_strncpy_read_str,
CONST_CAST (char *,
TREE_STRING_POINTER (str)),
MEM_ALIGN (target), false,
retmode);
if (exp_len > str_copy_len)
clear_storage (adjust_address (dest_mem, BLKmode, 0),
GEN_INT (exp_len - str_copy_len),
BLOCK_OP_NORMAL);
dest_mem = store_by_pieces (target, str_copy_len, string_cst_read_str,
(void *) str, MEM_ALIGN (target), false,
RETURN_END);
clear_storage (adjust_address (dest_mem, BLKmode, 0),
GEN_INT (exp_len - str_copy_len), BLOCK_OP_NORMAL);
return NULL_RTX;
}
else

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2019-02-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/66152
* gcc.target/i386/pr66152.c: New test.
2019-02-15 Eric Botcazou <ebotcazou@adacore.com>
* g++.dg/asan/asan_oob_test.cc: Skip OOB_int on SPARC.

25
gcc/testsuite/gcc.target/i386/pr66152.c Normal file
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@ -0,0 +1,25 @@
/* PR rtl-optimization/66152 */
/* { dg-do compile } */
/* { dg-options "-O2" } */
/* { dg-final { scan-assembler "movabs\[^\n\r]*506097522914230528" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler "movabs\[^\n\r]*505813836079825408" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler "mov\[^\n\r]*50462976" { target ia32 } } } */
/* { dg-final { scan-assembler "mov\[^\n\r]*117835012" { target ia32 } } } */
/* { dg-final { scan-assembler "mov\[^\n\r]*100925952" { target ia32 } } } */
/* { dg-final { scan-assembler "mov\[^\n\r]*117768961" { target ia32 } } } */
void foo (char *);
void
bar (void)
{
char a[] = {0,1,2,3,4,5,6,7};
foo (a);
}
void
baz (void)
{
char a[8] = "\0\2\4\6\1\3\5\7";
foo (a);
}