Add a few float shrinking optimizations to SimplifyLibCalls. Unsafe

optimizations are guarded by the -enable-double-float-shrink LLVM option.
Last bit of PR13574.  Patch by Weiming Zhao <weimingz@codeaurora.org>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162368 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 99 insertions, 36 deletions

diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 909ac8bde5..6add97625a 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -28,6 +28,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
@@ -38,6 +39,10 @@ using namespace llvm;
 STATISTIC(NumSimplified, "Number of library calls simplified");
 STATISTIC(NumAnnotated, "Number of attributes added to library functions");
 
+static cl::opt<bool> UnsafeFPShrink("enable-double-float-shrink", cl::Hidden,
+                                   cl::init(false),
+                                   cl::desc("Enable unsafe double to float "
+                                            "shrinking for math lib calls"));
 //===----------------------------------------------------------------------===//
 // Optimizer Base Class
 //===----------------------------------------------------------------------===//
@@ -893,16 +898,56 @@ struct MemSetOpt : public LibCallOptimization {
 //===----------------------------------------------------------------------===//
 
 //===---------------------------------------===//
-// 'cos*' Optimizations
+// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
+
+struct UnaryDoubleFPOpt : public LibCallOptimization {
+  bool CheckRetType;
+  UnaryDoubleFPOpt(bool CheckReturnType): CheckRetType(CheckReturnType) {}
+  virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    FunctionType *FT = Callee->getFunctionType();
+    if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
+        !FT->getParamType(0)->isDoubleTy())
+      return 0;
+
+    if (CheckRetType) {
+      // Check if all the uses for function like 'sin' are converted to float.
+      for (Value::use_iterator UseI = CI->use_begin(); UseI != CI->use_end();
+          ++UseI) {
+        FPTruncInst *Cast = dyn_cast<FPTruncInst>(*UseI);
+        if (Cast == 0 || !Cast->getType()->isFloatTy())
+          return 0;
+      }
+    }
+
+    // If this is something like 'floor((double)floatval)', convert to floorf.
+    FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
+    if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
+      return 0;
 
+    // floor((double)floatval) -> (double)floorf(floatval)
+    Value *V = Cast->getOperand(0);
+    V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
+    return B.CreateFPExt(V, B.getDoubleTy());
+  }
+};
+
+//===---------------------------------------===//
+// 'cos*' Optimizations
 struct CosOpt : public LibCallOptimization {
   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    Value *Ret = NULL;
+    if (UnsafeFPShrink && Callee->getName() == "cos" &&
+        TLI->has(LibFunc::cosf)) {
+      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
+      Ret = UnsafeUnaryDoubleFP.CallOptimizer(Callee, CI, B);
+    }
+
     FunctionType *FT = Callee->getFunctionType();
     // Just make sure this has 1 argument of FP type, which matches the
     // result type.
     if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
         !FT->getParamType(0)->isFloatingPointTy())
-      return 0;
+      return Ret;
 
     // cos(-x) -> cos(x)
     Value *Op1 = CI->getArgOperand(0);
@@ -910,7 +955,7 @@ struct CosOpt : public LibCallOptimization {
       BinaryOperator *BinExpr = cast<BinaryOperator>(Op1);
       return B.CreateCall(Callee, BinExpr->getOperand(1), "cos");
     }
-    return 0;
+    return Ret;
   }
 };
 
@@ -919,13 +964,20 @@ struct CosOpt : public LibCallOptimization {
 
 struct PowOpt : public LibCallOptimization {
   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    Value *Ret = NULL;
+    if (UnsafeFPShrink && Callee->getName() == "pow" &&
+        TLI->has(LibFunc::powf)) {
+      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
+      Ret = UnsafeUnaryDoubleFP.CallOptimizer(Callee, CI, B);
+    }
+
     FunctionType *FT = Callee->getFunctionType();
     // Just make sure this has 2 arguments of the same FP type, which match the
     // result type.
     if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
         FT->getParamType(0) != FT->getParamType(1) ||
         !FT->getParamType(0)->isFloatingPointTy())
-      return 0;
+      return Ret;
 
     Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
     if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
@@ -936,7 +988,7 @@ struct PowOpt : public LibCallOptimization {
     }
 
     ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
-    if (Op2C == 0) return 0;
+    if (Op2C == 0) return Ret;
 
     if (Op2C->getValueAPF().isZero())  // pow(x, 0.0) -> 1.0
       return ConstantFP::get(CI->getType(), 1.0);
@@ -974,12 +1026,19 @@ struct PowOpt : public LibCallOptimization {
 
 struct Exp2Opt : public LibCallOptimization {
   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    Value *Ret = NULL;
+    if (UnsafeFPShrink && Callee->getName() == "exp2" &&
+        TLI->has(LibFunc::exp2)) {
+      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
+      Ret = UnsafeUnaryDoubleFP.CallOptimizer(Callee, CI, B);
+    }
+
     FunctionType *FT = Callee->getFunctionType();
     // Just make sure this has 1 argument of FP type, which matches the
     // result type.
     if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
         !FT->getParamType(0)->isFloatingPointTy())
-      return 0;
+      return Ret;
 
     Value *Op = CI->getArgOperand(0);
     // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x))  if sizeof(x) <= 32
@@ -1016,29 +1075,7 @@ struct Exp2Opt : public LibCallOptimization {
 
       return CI;
     }
-    return 0;
-  }
-};
-
-//===---------------------------------------===//
-// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
-
-struct UnaryDoubleFPOpt : public LibCallOptimization {
-  virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
-        !FT->getParamType(0)->isDoubleTy())
-      return 0;
-
-    // If this is something like 'floor((double)floatval)', convert to floorf.
-    FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
-    if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
-      return 0;
-
-    // floor((double)floatval) -> (double)floorf(floatval)
-    Value *V = Cast->getOperand(0);
-    V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
-    return B.CreateFPExt(V, B.getDoubleTy());
+    return Ret;
   }
 };
 
@@ -1534,7 +1571,8 @@ namespace {
     StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
     MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
     // Math Library Optimizations
-    CosOpt Cos; PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
+    CosOpt Cos; PowOpt Pow; Exp2Opt Exp2;
+    UnaryDoubleFPOpt UnaryDoubleFP, UnsafeUnaryDoubleFP;
     // Integer Optimizations
     FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
     ToAsciiOpt ToAscii;
@@ -1547,7 +1585,8 @@ namespace {
   public:
     static char ID; // Pass identification
     SimplifyLibCalls() : FunctionPass(ID), StrCpy(false), StrCpyChk(true),
-                         StpCpy(false), StpCpyChk(true) {
+                         StpCpy(false), StpCpyChk(true),
+                         UnaryDoubleFP(false), UnsafeUnaryDoubleFP(true) {
       initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
     }
     void AddOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1651,11 +1690,35 @@ void SimplifyLibCalls::InitOptimizations() {
 
   AddOpt(LibFunc::ceil, LibFunc::ceilf, &UnaryDoubleFP);
   AddOpt(LibFunc::fabs, LibFunc::fabsf, &UnaryDoubleFP);
-  AddOpt(LibFunc::floor, LibFunc::floorf, &UnaryDoubleFP);
-  AddOpt(LibFunc::rint, LibFunc::rintf, &UnaryDoubleFP);
-  AddOpt(LibFunc::round, LibFunc::roundf, &UnaryDoubleFP);
-  AddOpt(LibFunc::nearbyint, LibFunc::nearbyintf, &UnaryDoubleFP);
-  AddOpt(LibFunc::trunc, LibFunc::truncf, &UnaryDoubleFP);
+  AddOpt(LibFunc::floor, LibFunc::floorf, &UnsafeUnaryDoubleFP);
+  AddOpt(LibFunc::rint, LibFunc::rintf, &UnsafeUnaryDoubleFP);
+  AddOpt(LibFunc::round, LibFunc::roundf, &UnsafeUnaryDoubleFP);
+  AddOpt(LibFunc::nearbyint, LibFunc::nearbyintf, &UnsafeUnaryDoubleFP);
+  AddOpt(LibFunc::trunc, LibFunc::truncf, &UnsafeUnaryDoubleFP);
+
+  if(UnsafeFPShrink) {
+    AddOpt(LibFunc::acos, LibFunc::acosf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::acosh, LibFunc::acoshf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::asin, LibFunc::asinf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::asinh, LibFunc::asinhf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::atan, LibFunc::atanf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::atanh, LibFunc::atanhf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::cbrt, LibFunc::cbrtf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::cosh, LibFunc::coshf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::exp, LibFunc::expf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::exp10, LibFunc::exp10f, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::expm1, LibFunc::expm1f, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::log, LibFunc::logf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::log10, LibFunc::log10f, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::log1p, LibFunc::log1pf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::log2, LibFunc::log2f, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::logb, LibFunc::logbf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::sin, LibFunc::sinf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::sinh, LibFunc::sinhf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::sqrt, LibFunc::sqrtf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::tan, LibFunc::tanf, &UnsafeUnaryDoubleFP);
+    AddOpt(LibFunc::tanh, LibFunc::tanhf, &UnsafeUnaryDoubleFP);
+  }
 
   // Integer Optimizations
   Optimizations["ffs"] = &FFS;