On Mon, Sep 29, 2014 at 01:08:56PM +0200, Jakub Jelinek wrote:
> I wonder if during/after reload we just couldn't look at
> ORIGINAL_REGNO of hard regs if ix86_use_pseudo_pic_reg. Or is that
> the other case, where you don't have any PIC register replacement around,
> and want to subtract something? Perhaps in that case we could just
> subtract the value of _GLOBAL_OFFSET_TABLE_ symbol if we have nothing better
> around.
Here is a patch that implements both of these ideas.
The number of lines like:
note: non-delegitimized UNSPEC UNSPEC_GOT (0) found in variable location
note: non-delegitimized UNSPEC UNSPEC_GOTOFF (1) found in variable location
during i686-linux bootstrap (not including regtest) went down from
14165 to 19.
The patch trusts that a hard reg with ORIGINAL_REGNO containing the pic
pseudo contains the _GLOBAL_OFFSET_TABLE_ value of the current shared
library (or binary), I think that is reasonable assumption.
And for ELF for the UNSPEC_GOTOFF it worse case can subtract
_GLOBAL_OFFSET_TABLE_ symbol if it doesn't know what register to subtract.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2014-10-21 Jakub Jelinek <ja...@redhat.com>
PR target/63542
* config/i386/i386.c (ix86_pic_register_p): Also return
true if x is a hard register with ORIGINAL_REGNO equal to
pic_offset_table_rtx pseudo REGNO.
(ix86_delegitimize_address): For ix86_use_pseudo_pic_reg ()
after reload, subtract GOT_SYMBOL_NAME symbol if possible.
* gcc.target/i386/pr63542-1.c: New test.
* gcc.target/i386/pr63542-2.c: New test.
--- gcc/config/i386/i386.c.jj 2014-10-21 11:51:30.000000000 +0200
+++ gcc/config/i386/i386.c 2014-10-21 13:06:55.621292368 +0200
@@ -14281,10 +14281,20 @@ ix86_pic_register_p (rtx x)
if (GET_CODE (x) == VALUE && CSELIB_VAL_PTR (x))
return (pic_offset_table_rtx
&& rtx_equal_for_cselib_p (x, pic_offset_table_rtx));
+ else if (!REG_P (x))
+ return false;
else if (pic_offset_table_rtx)
- return REG_P (x) && REGNO (x) == REGNO (pic_offset_table_rtx);
+ {
+ if (REGNO (x) == REGNO (pic_offset_table_rtx))
+ return true;
+ if (HARD_REGISTER_P (x)
+ && !HARD_REGISTER_P (pic_offset_table_rtx)
+ && ORIGINAL_REGNO (x) == REGNO (pic_offset_table_rtx))
+ return true;
+ return false;
+ }
else
- return REG_P (x) && REGNO (x) == PIC_OFFSET_TABLE_REGNUM;
+ return REGNO (x) == PIC_OFFSET_TABLE_REGNUM;
}
/* Helper function for ix86_delegitimize_address.
@@ -14457,15 +14467,20 @@ ix86_delegitimize_address (rtx x)
leal (%ebx, %ecx, 4), %ecx
...
movl foo@GOTOFF(%ecx), %edx
- in which case we return (%ecx - %ebx) + foo.
-
- Note that when pseudo_pic_reg is used we can generate it only
- before reload_completed. */
+ in which case we return (%ecx - %ebx) + foo
+ or (%ecx - _GLOBAL_OFFSET_TABLE_) + foo if pseudo_pic_reg
+ and reload has completed. */
if (pic_offset_table_rtx
&& (!reload_completed || !ix86_use_pseudo_pic_reg ()))
result = gen_rtx_PLUS (Pmode, gen_rtx_MINUS (Pmode, copy_rtx (addend),
pic_offset_table_rtx),
result);
+ else if (pic_offset_table_rtx && !TARGET_MACHO && !TARGET_VXWORKS_RTP)
+ {
+ rtx tmp = gen_rtx_SYMBOL_REF (Pmode, GOT_SYMBOL_NAME);
+ tmp = gen_rtx_MINUS (Pmode, copy_rtx (addend), tmp);
+ result = gen_rtx_PLUS (Pmode, tmp, result);
+ }
else
return orig_x;
}
--- gcc/testsuite/gcc.target/i386/pr63542-1.c.jj 2014-10-21
13:47:25.938470961 +0200
+++ gcc/testsuite/gcc.target/i386/pr63542-1.c 2014-10-21 13:48:26.227333649
+0200
@@ -0,0 +1,21 @@
+/* PR target/63542 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -g -dA" } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+float
+foo (long long u)
+{
+ if (!(-(1LL << 53) < u && u < (1LL << 53)))
+ {
+ if ((unsigned long long) u & ((1ULL << 11) - 1))
+ {
+ u &= ~((1ULL << 11) - 1);
+ u |= (1ULL << 11);
+ }
+ }
+ double f = (int) (u >> (32));
+ f *= 0x1p32f;
+ f += (unsigned int) u;
+ return (float) f;
+}
--- gcc/testsuite/gcc.target/i386/pr63542-2.c.jj 2014-10-21
13:47:29.084411447 +0200
+++ gcc/testsuite/gcc.target/i386/pr63542-2.c 2014-10-21 13:48:38.779096466
+0200
@@ -0,0 +1,37 @@
+/* PR target/63542 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -g -dA" } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+struct B { unsigned long c; unsigned char *d; };
+extern struct A { struct B *e[0x400]; } *f[128];
+extern void (*bar) (char *p, char *q);
+
+char *
+foo (char *p, char *q)
+{
+ struct B *g;
+ char *b, *l;
+ unsigned long s;
+
+ g = f[((unsigned long) p) >> 22]->e[(((unsigned long) p) >> 12) & 0x3ff];
+ s = g->c << 2;
+ int r = ((unsigned long) p) & 0xfff;
+ int m = g->d[r];
+ if (m > 0xfd)
+ {
+ m = (r >> 2) % (s >> 2);
+ if ((((unsigned long) p) & ~(unsigned long) 0xfff) != (((unsigned long)
q) & ~(unsigned long) 0xfff))
+ goto fail;
+ }
+ b = (char *) ((unsigned long) p & ~(unsigned long) 3);
+ b -= m << 2;
+ l = b + s;
+
+ if ( q >= l || q < b)
+ goto fail;
+ return p;
+fail:
+ (*bar) (p, q);
+ return p;
+}
Jakub
