mips.c (override_options): Default to no generation of branch-likely operations when...

2004-05-04  Chris Demetriou  <cgd@broadcom.com>

        * config/mips/mips.c (override_options): Default to no
        generation of branch-likely operations when tuning for
        CPUs where they tend to have a negative performance impact
        (e.g., SB-1).

From-SVN: r81494

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e0510a9..7547050 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2004-05-04  Chris Demetriou  <cgd@broadcom.com>
+
+       * config/mips/mips.c (override_options): Default to no
+       generation of branch-likely operations when tuning for
+       CPUs where they tend to have a negative performance impact
+       (e.g., SB-1).
+
 2004-05-04  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
        * expr.c (store_constructor_field): Don't call store_constructor

diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index ccb2b3f..d26626c 100644 (file)
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -4681,9 +4681,10 @@ override_options (void)
         architecture.
 
         By default, we enable use of Branch Likely instructions on
-        all architectures which support them except for MIPS32 and MIPS64
-        (i.e., the generic MIPS32 and MIPS64 ISAs, and processors which
-        implement them).
+        all architectures which support them with the following
+        exceptions: when creating MIPS32 or MIPS64 code, and when
+        tuning for architectures where their use tends to hurt
+        performance.
 
         The MIPS32 and MIPS64 architecture specifications say "Software
         is strongly encouraged to avoid use of Branch Likely
@@ -4691,7 +4692,9 @@ override_options (void)
         of the [MIPS32 and MIPS64] architecture."  Therefore, we do not
         issue those instructions unless instructed to do so by
         -mbranch-likely.  */
-      if (ISA_HAS_BRANCHLIKELY && !(ISA_MIPS32 || ISA_MIPS32R2 || ISA_MIPS64))
+      if (ISA_HAS_BRANCHLIKELY
+         && !(ISA_MIPS32 || ISA_MIPS32R2 || ISA_MIPS64)
+         && !(TUNE_SB1))
        target_flags |= MASK_BRANCHLIKELY;
       else
        target_flags &= ~MASK_BRANCHLIKELY;