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[PATCH/RFA] SH: Problem when compiling with -O0
- From: kaz Kojima <kkojima at rr dot iij4u dot or dot jp>
- To: gcc-patches at gcc dot gnu dot org
- Cc: joern dot rennecke at superh dot com, aoliva at redhat dot com
- Date: Sun, 29 Dec 2002 09:30:59 +0900
- Subject: [PATCH/RFA] SH: Problem when compiling with -O0
Hi,
For non-optimizing case, SH compiler sets the mode of a case vector
element to HImode even if its value is too big for HImode. This
prevents the bootstrap on mainline for sh-linux target. The 3.3
branch has the same problem.
The attached patch fixes it and makes sh4-unknown-linux-gnu compiler
bootstrap on mainline. There is one additional fail in regtest but
it isn't a new regression as explained bellow. Ok for 3.3-branch
and mainline?
This fix reveals an another problem with -O0 by chance. I found that
gcc.c-torture/compile/20001121-1.c failed with -O0 because compiler
wrongly generates a short conditional branch which jumps to the
label out of the short range -252..258 with a patched compiler. This
fail occurs also with -O0 -mbigtable for the same testcase on the
non-patched compiler.
It seems that since shorten_branches does only a single pass for
non-optimizing case, the expression (minus (match_dup 0) (pc)) in
the definition of short_cbranch_p results a smaller value based on
the maximal possible length of the conditional branch. In optimizing
case, it isn't a problem since the recomputation in shorten_branches
is done and the second try of (minus (match_dup 0) (pc)) returns
the correct value.
I guess that to recompute in shorten_branches always is the simplest
solution though I'm unsure it's the right thing to do.
Thought?
Regards,
kaz
--
2002-12-28 Kaz Kojima <kkojima@gcc.gnu.org>
* config/sh/sh.h (CASE_VECTOR_MODE): Use SImode for a
non-optimizing compile.
(ASM_OUTPUT_ADDR_VEC_ELT): Use .long for a non-optimizing
compile.
--- ORIG/gcc/gcc/config/sh/sh.h Tue Dec 17 07:06:35 2002
+++ LOCAL/gcc/gcc/config/sh/sh.h Thu Dec 27 14:59:10 2002
@@ -2571,7 +2571,7 @@ while (0)
/* Specify the machine mode that this machine uses
for the index in the tablejump instruction. */
-#define CASE_VECTOR_MODE (TARGET_BIGTABLE ? SImode : HImode)
+#define CASE_VECTOR_MODE ((! optimize || TARGET_BIGTABLE) ? SImode : HImode)
#define CASE_VECTOR_SHORTEN_MODE(MIN_OFFSET, MAX_OFFSET, BODY) \
((MIN_OFFSET) >= 0 && (MAX_OFFSET) <= 127 \
@@ -3041,7 +3041,7 @@ while (0)
/* Output an absolute table element. */
#define ASM_OUTPUT_ADDR_VEC_ELT(STREAM,VALUE) \
- if (TARGET_BIGTABLE) \
+ if (! optimize || TARGET_BIGTABLE) \
asm_fprintf ((STREAM), "\t.long\t%LL%d\n", (VALUE)); \
else \
asm_fprintf ((STREAM), "\t.word\t%LL%d\n", (VALUE));