[PowerPC] Make use of the TargetRecip system

[oota-llvm.git] / lib / Target / PowerPC / PPCTargetMachine.cpp

diff --git a/lib/Target/PowerPC/PPCTargetMachine.cpp b/lib/Target/PowerPC/PPCTargetMachine.cpp
index 074bc870751ac75113628b4efb72cd6b83789891..1daf244fed448818ff541c50371077668df4b47d 100644 (file)
--- a/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -172,7 +172,26 @@ PPCTargetMachine::PPCTargetMachine(const Target &T, const Triple &TT,
     : LLVMTargetMachine(T, getDataLayoutString(TT), TT, CPU,
                         computeFSAdditions(FS, OL, TT), Options, RM, CM, OL),
       TLOF(createTLOF(getTargetTriple())),
-      TargetABI(computeTargetABI(TT, Options)) {
+      TargetABI(computeTargetABI(TT, Options)),
+      Subtarget(TargetTriple, CPU, computeFSAdditions(FS, OL, TT), *this) {
+
+  // For the estimates, convergence is quadratic, so we essentially double the
+  // number of digits correct after every iteration. For both FRE and FRSQRTE,
+  // the minimum architected relative accuracy is 2^-5. When hasRecipPrec(),
+  // this is 2^-14. IEEE float has 23 digits and double has 52 digits.
+  unsigned RefinementSteps = Subtarget.hasRecipPrec() ? 1 : 3,
+           RefinementSteps64 = RefinementSteps + 1;
+
+  this->Options.Reciprocals.setDefaults("sqrtf", true, RefinementSteps);
+  this->Options.Reciprocals.setDefaults("vec-sqrtf", true, RefinementSteps);
+  this->Options.Reciprocals.setDefaults("divf", true, RefinementSteps);
+  this->Options.Reciprocals.setDefaults("vec-divf", true, RefinementSteps);
+
+  this->Options.Reciprocals.setDefaults("sqrtd", true, RefinementSteps64);
+  this->Options.Reciprocals.setDefaults("vec-sqrtd", true, RefinementSteps64);
+  this->Options.Reciprocals.setDefaults("divd", true, RefinementSteps64);
+  this->Options.Reciprocals.setDefaults("vec-divd", true, RefinementSteps64);
+
   initAsmInfo();
 }