From: Richard Henderson <rth@redhat.com>
Date: Wed, 3 Aug 2011 22:57:22 +0000 (-0700)
Subject: re PR target/34888 (Stack patterns for AVR not optimal)
X-Git-Tag: releases/gcc-4.7.0~4749
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a6365e997e0ea5f378e811d4649fd53c55510c69;p=thirdparty%2Fgcc.git

re PR target/34888 (Stack patterns for AVR not optimal)

PR target/34888
        * config/avr/avr.md: New splitter for REG_ARGS_SIZE 0.

From-SVN: r177300
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2b7073892475..a6f6b5689677 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-03  Richard Henderson  <rth@redhat.com>
+
+	PR target/34888
+	* config/avr/avr.md: New splitter for REG_ARGS_SIZE 0.
+
 2011-08-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/49948
diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index b8560df60d46..b5aa73c55f28 100644
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -235,6 +235,17 @@
   DONE;
 })
 
+;; Notice a special-case when adding N to SP where N results in a
+;; zero REG_ARGS_SIZE.  This is equivalent to a move from FP.
+(define_split
+  [(set (reg:HI REG_SP) (match_operand:HI 0 "register_operand" ""))]
+  "reload_completed
+   && frame_pointer_needed
+   && !cfun->calls_alloca
+   && find_reg_note (insn, REG_ARGS_SIZE, const0_rtx)"
+  [(set (reg:HI REG_SP) (reg:HI REG_Y))]
+  "")
+
 ;;========================================================================
 ;; move byte
 ;; The last alternative (any immediate constant to any register) is