[llvm-commits] [llvm] r158294 - /llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp

[Hal Finkel]

Author: hfinkel
Date: Sun Jun 10 06:15:36 2012
New Revision: 158294

URL: http://llvm.org/viewvc/llvm-project?rev=158294&view=rev
Log:
Use critical anti-dep. breaking on all PPC targets, but also add other register classes.

Using 'all' instead of 'critical' would be better because it would make it easier to
satisfy the bundling constraints, but, as noted in the FIXME, that is currently not
possible with the crs.

This yields an average 1% speedup over the entire test suite (on Power 7). Largest speedups:
SingleSource/Benchmarks/Shootout-C++/moments - 40%
MultiSource/Benchmarks/McCat/03-testtrie/testtrie - 28%
SingleSource/Benchmarks/BenchmarkGame/nsieve-bits - 26%
SingleSource/Benchmarks/McGill/misr - 23%
MultiSource/Applications/JM/ldecod/ldecod - 22%

Largest slowdowns:
SingleSource/Benchmarks/Shootout-C++/matrix - -29%
SingleSource/Benchmarks/Shootout-C++/ary3 - -22%
MultiSource/Benchmarks/BitBench/uuencode/uuencode - -18%
SingleSource/Benchmarks/Shootout-C++/ary - -17%
MultiSource/Benchmarks/MiBench/automotive-bitcount/automotive-bitcount - -15%

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp?rev=158294&r1=158293&r2=158294&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp Sun Jun 10 06:15:36 2012
@@ -146,10 +146,14 @@
            CodeGenOpt::Level OptLevel,
            TargetSubtargetInfo::AntiDepBreakMode& Mode,
            RegClassVector& CriticalPathRCs) const {
-  if (DarwinDirective == PPC::DIR_440 || DarwinDirective == PPC::DIR_A2)
-    Mode = TargetSubtargetInfo::ANTIDEP_ALL;
-  else
-    Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
+  // FIXME: It would be best to use TargetSubtargetInfo::ANTIDEP_ALL here,
+  // but we can't because we can't reassign the cr registers. There is a
+  // dependence between the cr register and the RLWINM instruction used
+  // to extract its value which the anti-dependency breaker can't currently
+  // see. Maybe we should make a late-expanded pseudo to encode this dependency.
+  // (the relevant code is in PPCDAGToDAGISel::SelectSETCC)
+
+  Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
 
   CriticalPathRCs.clear();
 
@@ -157,6 +161,9 @@
     CriticalPathRCs.push_back(&PPC::G8RCRegClass);
   else
     CriticalPathRCs.push_back(&PPC::GPRCRegClass);
+    
+  CriticalPathRCs.push_back(&PPC::F8RCRegClass);
+  CriticalPathRCs.push_back(&PPC::VRRCRegClass);
 
   return OptLevel >= CodeGenOpt::Default;
 }