| Message ID | 20110513145721.2fbe289b@rex.config |
|---|---|
| State | New |
| Headers | show |
On 13/05/11 14:57, Julian Brown wrote: > As per Joseph's suggestion here: > > http://gcc.gnu.org/ml/gcc-patches/2011-05/msg00846.html > > I am re-posting machine-independent parts of my ARM fixed-point support > patches, with explanations as to why each part is necessary. > > This is the first: on ARM, TARGET_LIB_INT_CMP_BIASED is false for > TARGET_BPABI targets (i.e. most currently-interesting cases -- > EABI comparison helper functions return -1/0/1 for lt/eq/gt rather than > 0/1/2). However the fixed-point helper library uses biased comparisons > unconditionally. So, this patch just makes comparisons between > fixed-point quantities use the biasing rather than not. (Grepping > config/, in practice, this will only affect ARM.) > > Tested in a series with other fixed-point patches. OK to apply? > > Julian > > ChangeLog > > gcc/ > * optabs.c (prepare_cmp_insn): Use correct biasing for fixed-point > comparison helpers. > OK. R.
commit 12efebd5f56358c2d194659570ad05e089bbaaf3
Author: Julian Brown <julian@henry8.codesourcery.com>
Date: Fri May 13 05:42:15 2011 -0700
Correct biasing for fixed-point optabs.
diff --git a/gcc/optabs.c b/gcc/optabs.c
index 62e123b..a1b85b8 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -3930,11 +3930,13 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx_code comparison, rtx size,
result against 1 in the biased case, and zero in the unbiased
case. For unsigned comparisons always compare against 1 after
biasing the unbiased result by adding 1. This gives us a way to
- represent LTU. */
+ represent LTU.
+ The comparisons in the fixed-point helper library are always
+ biased. */
x = result;
y = const1_rtx;
- if (!TARGET_LIB_INT_CMP_BIASED)
+ if (!TARGET_LIB_INT_CMP_BIASED && !ALL_FIXED_POINT_MODE_P (mode))
{
if (unsignedp)
x = plus_constant (result, 1);
As per Joseph's suggestion here: http://gcc.gnu.org/ml/gcc-patches/2011-05/msg00846.html I am re-posting machine-independent parts of my ARM fixed-point support patches, with explanations as to why each part is necessary. This is the first: on ARM, TARGET_LIB_INT_CMP_BIASED is false for TARGET_BPABI targets (i.e. most currently-interesting cases -- EABI comparison helper functions return -1/0/1 for lt/eq/gt rather than 0/1/2). However the fixed-point helper library uses biased comparisons unconditionally. So, this patch just makes comparisons between fixed-point quantities use the biasing rather than not. (Grepping config/, in practice, this will only affect ARM.) Tested in a series with other fixed-point patches. OK to apply? Julian ChangeLog gcc/ * optabs.c (prepare_cmp_insn): Use correct biasing for fixed-point comparison helpers.