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Limit SH strncmp inline expansion (PR target/78460)
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <gcc-patches at gcc dot gnu dot org>
- Cc: <aoliva at redhat dot com>, <olegendo at gcc dot gnu dot org>
- Date: Tue, 15 Aug 2017 21:15:35 +0000
- Subject: Limit SH strncmp inline expansion (PR target/78460)
- Authentication-results: sourceware.org; auth=none
GCC mainline built for sh4-linux-gnu runs out of memory building a
glibc test, which calls strncmp with very large constant size
argument, resulting in the SH inline strncmp expansion trying to
inline a fully unrolled expansion of strncmp for that size.
This patch limits that fully unrolled expansion to the case of less
than 32 bytes. This is explicitly *not* trying to be optimal in any
way (very likely a lower threshold makes sense), just to limit enough
to avoid the out-of-memory issue in the glibc testsuite.
I have *not* run the GCC testsuite for SH. I have verified that this
allows the glibc testsuite to build OK, with both GCC mainline and GCC
7 branch (and that the included test builds quickly with patched GCC,
runs out of memory with unpatched GCC).
OK to commit (mainline and GCC 7 branch)?
gcc:
2017-08-15 Joseph Myers <joseph@codesourcery.com>
PR target/78460
* config/sh/sh-mem.cc (sh_expand_cmpnstr): Only unroll for
constant count if that count is less than 32.
gcc/testsuite:
2017-08-15 Joseph Myers <joseph@codesourcery.com>
PR target/78460
* gcc.c-torture/compile/string-large-1.c: New test.
Index: gcc/config/sh/sh-mem.cc
===================================================================
--- gcc/config/sh/sh-mem.cc (revision 251105)
+++ gcc/config/sh/sh-mem.cc (working copy)
@@ -349,12 +349,13 @@ sh_expand_cmpnstr (rtx *operands)
rtx len = copy_to_mode_reg (SImode, operands[3]);
int constp = CONST_INT_P (operands[3]);
+ HOST_WIDE_INT bytes = constp ? INTVAL (operands[3]) : 0;
const unsigned int addr1_alignment = MEM_ALIGN (operands[1]) / BITS_PER_UNIT;
const unsigned int addr2_alignment = MEM_ALIGN (operands[2]) / BITS_PER_UNIT;
/* Loop on a register count. */
- if (constp)
+ if (constp && bytes >= 0 && bytes < 32)
{
rtx tmp0 = gen_reg_rtx (SImode);
rtx tmp3 = gen_reg_rtx (SImode);
@@ -363,7 +364,6 @@ sh_expand_cmpnstr (rtx *operands)
rtx_code_label *L_loop_long = gen_label_rtx ();
rtx_code_label *L_end_loop_long = gen_label_rtx ();
- int bytes = INTVAL (operands[3]);
int witers = bytes / 4;
if (witers > 1)
Index: gcc/testsuite/gcc.c-torture/compile/string-large-1.c
===================================================================
--- gcc/testsuite/gcc.c-torture/compile/string-large-1.c (nonexistent)
+++ gcc/testsuite/gcc.c-torture/compile/string-large-1.c (working copy)
@@ -0,0 +1,119 @@
+/* Test built-in string functions with large sizes. PR 78460. */
+
+typedef __SIZE_TYPE__ size_t;
+
+#define SIZE1 ((size_t) -1)
+#define SIZE2 (SIZE1 >> 1)
+#define SIZE3 ((unsigned int) -1)
+#define SIZE4 (SIZE3 >> 1)
+
+volatile int v1, v2, v3, v4;
+void *volatile vp1, *volatile vp2, *volatile vp3, *volatile vp4;
+
+void
+test_memchr (const void *a, int b)
+{
+ vp1 = __builtin_memchr (a, b, SIZE1);
+ vp2 = __builtin_memchr (a, b, SIZE2);
+ vp3 = __builtin_memchr (a, b, SIZE3);
+ vp4 = __builtin_memchr (a, b, SIZE4);
+}
+
+void
+test_memcmp (const void *a, const void *b)
+{
+ v1 = __builtin_memcmp (a, b, SIZE1);
+ v2 = __builtin_memcmp (a, b, SIZE2);
+ v3 = __builtin_memcmp (a, b, SIZE3);
+ v4 = __builtin_memcmp (a, b, SIZE4);
+}
+
+void
+test_memcpy (void *a, const void *b)
+{
+ vp1 = __builtin_memcpy (a, b, SIZE1);
+ vp2 = __builtin_memcpy (a, b, SIZE2);
+ vp3 = __builtin_memcpy (a, b, SIZE3);
+ vp4 = __builtin_memcpy (a, b, SIZE4);
+}
+
+void
+test_memmove (void *a, const void *b)
+{
+ vp1 = __builtin_memmove (a, b, SIZE1);
+ vp2 = __builtin_memmove (a, b, SIZE2);
+ vp3 = __builtin_memmove (a, b, SIZE3);
+ vp4 = __builtin_memmove (a, b, SIZE4);
+}
+
+void
+test_mempcpy (void *a, const void *b)
+{
+ vp1 = __builtin_mempcpy (a, b, SIZE1);
+ vp2 = __builtin_mempcpy (a, b, SIZE2);
+ vp3 = __builtin_mempcpy (a, b, SIZE3);
+ vp4 = __builtin_mempcpy (a, b, SIZE4);
+}
+
+void
+test_memset (void *a, int b)
+{
+ vp1 = __builtin_memset (a, b, SIZE1);
+ vp2 = __builtin_memset (a, b, SIZE2);
+ vp3 = __builtin_memset (a, b, SIZE3);
+ vp4 = __builtin_memset (a, b, SIZE4);
+}
+
+void
+test_stpncpy (char *a, const char *b)
+{
+ vp1 = __builtin_stpncpy (a, b, SIZE1);
+ vp2 = __builtin_stpncpy (a, b, SIZE2);
+ vp3 = __builtin_stpncpy (a, b, SIZE3);
+ vp4 = __builtin_stpncpy (a, b, SIZE4);
+}
+
+void
+test_strndup (const char *a)
+{
+ vp1 = __builtin_strndup (a, SIZE1);
+ vp2 = __builtin_strndup (a, SIZE2);
+ vp3 = __builtin_strndup (a, SIZE3);
+ vp4 = __builtin_strndup (a, SIZE4);
+}
+
+void
+test_strncasecmp (const char *a, const char *b)
+{
+ v1 = __builtin_strncasecmp (a, b, SIZE1);
+ v2 = __builtin_strncasecmp (a, b, SIZE2);
+ v3 = __builtin_strncasecmp (a, b, SIZE3);
+ v4 = __builtin_strncasecmp (a, b, SIZE4);
+}
+
+void
+test_strncat (char *a, const char *b)
+{
+ vp1 = __builtin_strncat (a, b, SIZE1);
+ vp2 = __builtin_strncat (a, b, SIZE2);
+ vp3 = __builtin_strncat (a, b, SIZE3);
+ vp4 = __builtin_strncat (a, b, SIZE4);
+}
+
+void
+test_strncmp (const char *a, const char *b)
+{
+ v1 = __builtin_strncmp (a, b, SIZE1);
+ v2 = __builtin_strncmp (a, b, SIZE2);
+ v3 = __builtin_strncmp (a, b, SIZE3);
+ v4 = __builtin_strncmp (a, b, SIZE4);
+}
+
+void
+test_strncpy (char *a, const char *b)
+{
+ vp1 = __builtin_strncpy (a, b, SIZE1);
+ vp2 = __builtin_strncpy (a, b, SIZE2);
+ vp3 = __builtin_strncpy (a, b, SIZE3);
+ vp4 = __builtin_strncpy (a, b, SIZE4);
+}
--
Joseph S. Myers
joseph@codesourcery.com