From 437b107671a1dbe254ce488de1316ab082552331 Mon Sep 17 00:00:00 2001
From: Peter Zotov <whitequark@whitequark.org>
Date: Tue, 28 Oct 2014 19:46:44 +0000
Subject: [PATCH] [C API] PR19859: Add LLVMGetFCmpPredicate and
 LLVMConstRealGetDouble.

Patch by Gabriel Radanne <drupyog@zoho.com>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220814 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm-c/Core.h | 18 ++++++++++++++++++
 lib/IR/Core.cpp       | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/include/llvm-c/Core.h b/include/llvm-c/Core.h
index 4f9da09a6d8..485cf9481f2 100644
--- a/include/llvm-c/Core.h
+++ b/include/llvm-c/Core.h
@@ -1548,6 +1548,14 @@ unsigned long long LLVMConstIntGetZExtValue(LLVMValueRef ConstantVal);
  */
 long long LLVMConstIntGetSExtValue(LLVMValueRef ConstantVal);
 
+/**
+ * Obtain the double value for an floating point constant value.
+ * losesInfo indicates if some precision was lost in the conversion.
+ *
+ * @see llvm::ConstantFP::getDoubleValue
+ */
+double LLVMConstRealGetDouble(LLVMValueRef ConstantVal, LLVMBool *losesInfo);
+
 /**
  * @}
  */
@@ -2408,6 +2416,16 @@ LLVMOpcode   LLVMGetInstructionOpcode(LLVMValueRef Inst);
  */
 LLVMIntPredicate LLVMGetICmpPredicate(LLVMValueRef Inst);
 
+/**
+ * Obtain the float predicate of an instruction.
+ *
+ * This is only valid for instructions that correspond to llvm::FCmpInst
+ * or llvm::ConstantExpr whose opcode is llvm::Instruction::FCmp.
+ *
+ * @see llvm::FCmpInst::getPredicate()
+ */
+LLVMRealPredicate LLVMGetFCmpPredicate(LLVMValueRef Inst);
+
 /**
  * Create a copy of 'this' instruction that is identical in all ways
  * except the following:
diff --git a/lib/IR/Core.cpp b/lib/IR/Core.cpp
index f1e134233e6..e8cfc79679d 100644
--- a/lib/IR/Core.cpp
+++ b/lib/IR/Core.cpp
@@ -774,6 +774,27 @@ long long LLVMConstIntGetSExtValue(LLVMValueRef ConstantVal) {
   return unwrap<ConstantInt>(ConstantVal)->getSExtValue();
 }
 
+double LLVMConstRealGetDouble(LLVMValueRef ConstantVal, LLVMBool *LosesInfo) {
+  ConstantFP *cFP = unwrap<ConstantFP>(ConstantVal) ;
+  Type *Ty = cFP->getType();
+
+  if (Ty->isFloatTy()) {
+    *LosesInfo = false;
+    return cFP->getValueAPF().convertToFloat();
+  }
+
+  if (Ty->isDoubleTy()) {
+    *LosesInfo = false;
+    return cFP->getValueAPF().convertToDouble();
+  }
+
+  bool APFLosesInfo;
+  APFloat APF = cFP->getValueAPF();
+  APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, &APFLosesInfo);
+  *LosesInfo = APFLosesInfo;
+  return APF.convertToDouble();
+}
+
 /*--.. Operations on composite constants ...................................--*/
 
 LLVMValueRef LLVMConstStringInContext(LLVMContextRef C, const char *Str,
@@ -1882,6 +1903,15 @@ LLVMIntPredicate LLVMGetICmpPredicate(LLVMValueRef Inst) {
   return (LLVMIntPredicate)0;
 }
 
+LLVMRealPredicate LLVMGetFCmpPredicate(LLVMValueRef Inst) {
+  if (FCmpInst *I = dyn_cast<FCmpInst>(unwrap(Inst)))
+    return (LLVMRealPredicate)I->getPredicate();
+  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(unwrap(Inst)))
+    if (CE->getOpcode() == Instruction::FCmp)
+      return (LLVMRealPredicate)CE->getPredicate();
+  return (LLVMRealPredicate)0;
+}
+
 LLVMOpcode LLVMGetInstructionOpcode(LLVMValueRef Inst) {
   if (Instruction *C = dyn_cast<Instruction>(unwrap(Inst)))
     return map_to_llvmopcode(C->getOpcode());
@@ -2342,7 +2372,7 @@ static AtomicOrdering mapFromLLVMOrdering(LLVMAtomicOrdering Ordering) {
     case LLVMAtomicOrderingSequentiallyConsistent:
       return SequentiallyConsistent;
   }
-  
+
   llvm_unreachable("Invalid LLVMAtomicOrdering value!");
 }
 
-- 
2.34.1