From e4ffbd30b5e5d8dffc3705e0b765515741e6fa26 Mon Sep 17 00:00:00 2001 From: ebotcazou Date: Tue, 22 Mar 2011 20:04:58 +0000 Subject: [PATCH] * combine.c (simplify_set): Try harder to find the best CC mode when simplifying a nested COMPARE on the RHS. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@171304 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 5 +++++ gcc/combine.c | 16 +++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index efe5aa10e4e..a6fa3ddfc8c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2011-03-22 Eric Botcazou + + * combine.c (simplify_set): Try harder to find the best CC mode when + simplifying a nested COMPARE on the RHS. + 2011-03-22 Joseph Myers * config/alpha/gnu.h: Remove. diff --git a/gcc/combine.c b/gcc/combine.c index fe3302a492d..60bd9eedd55 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -6240,10 +6240,18 @@ simplify_set (rtx x) enum rtx_code new_code; rtx op0, op1, tmp; int other_changed = 0; + rtx inner_compare = NULL_RTX; enum machine_mode compare_mode = GET_MODE (dest); if (GET_CODE (src) == COMPARE) - op0 = XEXP (src, 0), op1 = XEXP (src, 1); + { + op0 = XEXP (src, 0), op1 = XEXP (src, 1); + if (GET_CODE (op0) == COMPARE && op1 == const0_rtx) + { + inner_compare = op0; + op0 = XEXP (inner_compare, 0), op1 = XEXP (inner_compare, 1); + } + } else op0 = src, op1 = CONST0_RTX (GET_MODE (src)); @@ -6285,6 +6293,12 @@ simplify_set (rtx x) need to use a different CC mode here. */ if (GET_MODE_CLASS (GET_MODE (op0)) == MODE_CC) compare_mode = GET_MODE (op0); + else if (inner_compare + && GET_MODE_CLASS (GET_MODE (inner_compare)) == MODE_CC + && new_code == old_code + && op0 == XEXP (inner_compare, 0) + && op1 == XEXP (inner_compare, 1)) + compare_mode = GET_MODE (inner_compare); else compare_mode = SELECT_CC_MODE (new_code, op0, op1); -- 2.11.4.GIT