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changeset 9699:5dda6f5397ff

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8075093: Enable UseFPUForSpilling support on SPARC Summary: Use single-cycle MOV instructions (MOVdTOx, MOVxTOd) for spills on SPARC which have them. Reviewed-by: kvn Contributed-by: shrinivas.joshi@oracle.com
author kvn
date Wed, 02 Sep 2015 15:11:22 -0700
parents 82b61ad9f45f
children 979c4f71a3c8
files src/cpu/sparc/vm/vm_version_sparc.cpp
diffstat 1 files changed, 12 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/src/cpu/sparc/vm/vm_version_sparc.cpp	Wed Sep 02 22:05:47 2015 +0200
+++ b/src/cpu/sparc/vm/vm_version_sparc.cpp	Wed Sep 02 15:11:22 2015 -0700
@@ -218,9 +218,6 @@
     FLAG_SET_DEFAULT(UseRDPCForConstantTableBase, true);
   }
 
-  // Currently not supported anywhere.
-  FLAG_SET_DEFAULT(UseFPUForSpilling, false);
-
   MaxVectorSize = 8;
 
   assert((InteriorEntryAlignment % relocInfo::addr_unit()) == 0, "alignment is not a multiple of NOP size");
@@ -266,6 +263,18 @@
   if (!has_vis1()) // Drop to 0 if no VIS1 support
     UseVIS = 0;
 
+  // Enable UseFPUForSpilling if low-latency GP-to-FP register move instructions are available
+  if (UseVIS > 2) { // FP spill use VIS3 MOVxTOd/MOVdTOx
+    if (FLAG_IS_DEFAULT(UseFPUForSpilling)) {
+      FLAG_SET_DEFAULT(UseFPUForSpilling, true);
+    }
+  } else if (UseFPUForSpilling) {
+    if (!FLAG_IS_DEFAULT(UseFPUForSpilling)) {
+      warning("Spill to float registers requires VIS3 instructions (not available on this CPU).");
+    }
+    FLAG_SET_DEFAULT(UseFPUForSpilling, false);
+  }
+
   // SPARC T4 and above should have support for AES instructions
   if (has_aes()) {
     if (UseVIS > 2) { // AES intrinsics use MOVxTOd/MOVdTOx which are VIS3