[PATCH] recog: Disallow changes in asms for reg asm ("x") operands
Andreas Krebbel
krebbel@linux.vnet.ibm.com
Mon Feb 23 16:06:00 GMT 2009
Hi,
in the attached testcase RTL loop invariant motion replaces the output
register of the inline assembly with a pseudo. I don't think this is a
valid change since the register asm("0") definition of r0 should be
binding for the inline assembly.
The attached patch adds a check to verify_changes which prevents such
changes from being done when the respective declaration requires a
specific hard reg.
This fixes the testcase which is currently failing on s390 and s390x.
Bootstrapped on s390 and s390x - x86_64 still running.
Ok for mainline - given the x86_64 is clean?
Bye,
-Andreas-
2009-02-23 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
* recog.c (verfiy_changes): Disallow renaming of hard regs in
inline asms for register asm ("") declarations.
2009-02-23 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
* gcc.target/s390/20090223-1.c: New testcase.
Index: gcc/gcc/recog.c
===================================================================
--- gcc.orig/gcc/recog.c
+++ gcc/gcc/recog.c
@@ -379,6 +379,16 @@ verify_changes (int num)
if (! memory_address_p (GET_MODE (object), XEXP (object, 0)))
break;
}
+ else if (REG_P (changes[i].old)
+ && asm_noperands (PATTERN (object)) > 0
+ && REG_EXPR (changes[i].old) != NULL_TREE
+ && DECL_ASSEMBLER_NAME_SET_P (REG_EXPR (changes[i].old))
+ && DECL_REGISTER (REG_EXPR (changes[i].old)))
+ {
+ /* Don't allow changes of hard register operands to inline
+ assemblies if they have been defined as register asm ("x"). */
+ break;
+ }
else if (insn_invalid_p (object))
{
rtx pat = PATTERN (object);
Index: gcc/gcc/testsuite/gcc.target/s390/20090223-1.c
===================================================================
--- /dev/null
+++ gcc/gcc/testsuite/gcc.target/s390/20090223-1.c
@@ -0,0 +1,60 @@
+/* The RTL loop optimizer used to replace the output register of the
+ inline assembly with a pseudo although the variable is declared as
+ register asm ("0"). */
+
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+
+static unsigned char __attribute__ ((always_inline))
+mytoupper (unsigned char c)
+{
+ if (c >= 'a' && c <= 'z')
+ c -= 'a' - 'A';
+ return c;
+}
+
+static unsigned long __attribute__ ((always_inline))
+strlen (const char *s)
+{
+ register unsigned long r0 asm ("0");
+ const char *tmp = s;
+
+ asm (
+#ifdef __s390x__
+ " lghi %0, 0\n"
+#else
+ " lhi %0, 0\n"
+#endif
+ "0:srst %0,%1\n"
+ " jo 0b"
+ : "=d" (r0), "+a" (tmp)
+ :
+ :"cc");
+ return r0 - (unsigned long) s;
+}
+
+char boot_command_line[] = "this is a test";
+
+void __attribute__ ((noinline))
+foo (char *str)
+{
+ if (strcmp (str, "THIS IS A TEST") != 0)
+ abort ();
+}
+
+int
+main ()
+{
+ char upper_command_line[1024];
+ int i;
+
+ for (i = 0; i < strlen (boot_command_line); i++)
+ upper_command_line[i] = mytoupper (boot_command_line[i]);
+
+ upper_command_line[strlen (boot_command_line)] = 0;
+ foo (upper_command_line);
+
+ return 0;
+}
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