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Fix PR target/16494
- From: Eric Botcazou <ebotcazou at libertysurf dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 13 Jul 2004 13:54:52 +0200
- Subject: Fix PR target/16494
I discovered this yesterday: on non-V9 targets, when delay slots are not
filled, FP conditional branches are unnecessarily reversed. See the PR for
an example.
This was inadvertently introduced by:
2003-10-01 Eric Botcazou <ebotcazou@libertysurf.fr>
PR optimization/11753
* config/sparc/sparc.md (length attribute) [fcc branch]: Add 1 to
the length in the non-V9 case.
because there is an "undocumented" side-effect associated with having a
length greater or equal to 3 for conditional branches: output_cbranch will
automatically reverse the branch. *sigh*
Fixed by restricting the feature to the V9 case and adding a warning.
Bootstrapped/regtested on sparc64-sun-solaris2.9, sparc-sun-solaris2.8,
sparc-sun-solaris2.7, sparc-sun-solaris2.6 and sparc-sun-solaris2.5.1.
Applied to all active branches.
2004-07-13 Eric Botcazou <ebotcazou@libertysurf.fr>
PR target/16494
* config/sparc/sparc.c (output_cbranch): Properly guard
the code handling far branches with TARGET_V9.
* config/sparc/sparc.md (length attribute): Document the
side-effect of having a length greater or equal to 3.
--
Eric Botcazou
Index: config/sparc/sparc.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/sparc.c,v
retrieving revision 1.233.4.10
diff -u -p -r1.233.4.10 sparc.c
--- config/sparc/sparc.c 31 May 2004 21:45:32 -0000 1.233.4.10
+++ config/sparc/sparc.c 12 Jul 2004 13:20:12 -0000
@@ -5491,7 +5491,7 @@ output_cbranch (op, dest, label, reverse
nop
ba .LC29 */
- far = get_attr_length (insn) >= 3;
+ far = TARGET_V9 && (get_attr_length (insn) >= 3);
if (reversed ^ far)
{
/* Reversal of FP compares takes care -- an ordered compare
@@ -5621,9 +5621,7 @@ output_cbranch (op, dest, label, reverse
spaces -= 2;
}
- if (! TARGET_V9)
- labelno = "";
- else
+ if (TARGET_V9)
{
rtx note;
int v8 = 0;
@@ -5673,6 +5671,9 @@ output_cbranch (op, dest, label, reverse
spaces -= 3;
}
}
+ else
+ labelno = "";
+
if (spaces > 0)
*p++ = '\t';
else
Index: config/sparc/sparc.md
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/sparc.md,v
retrieving revision 1.181.4.11
diff -u -p -r1.181.4.11 sparc.md
--- config/sparc/sparc.md 31 May 2004 21:45:33 -0000 1.181.4.11
+++ config/sparc/sparc.md 12 Jul 2004 13:20:22 -0000
@@ -120,6 +120,8 @@
(symbol_ref "TARGET_FLAT != 0"))
;; Length (in # of insns).
+;; Beware that setting a length greater or equal to 3 for conditional branches
+;; has a side-effect (see output_cbranch and output_v9branch).
(define_attr "length" ""
(cond [(eq_attr "type" "uncond_branch,call,sibcall")
(if_then_else (eq_attr "empty_delay_slot" "true")