Revert "Revert "[APFloat] Removed APFloat constructor which initialized to either zero/NaN but allowed you to arbitrarily set the category of the float.""

This reverts commit r185099.

Looks like both the ppc-64 and mips bots are still failing after I reverted this
change.

Since:

1. The mips bot always performs a clean build,
2. The ppc64-bot failed again after a clean build (I asked the ppc-64
maintainers to clean the bot which they did... Thanks Will!),

I think it is safe to assume that this change was not the cause of the failures
that said builders were seeing. Thus I am recomitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185111 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index af8a479..617d8e7 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2888,7 +2888,7 @@
   if (!LHSUnsigned) {
     // If the RHS value is > SignedMax, fold the comparison.  This handles +INF
     // and large values.
-    APFloat SMax(RHS.getSemantics(), APFloat::fcZero, false);
+    APFloat SMax(RHS.getSemantics());
     SMax.convertFromAPInt(APInt::getSignedMaxValue(IntWidth), true,
                           APFloat::rmNearestTiesToEven);
     if (SMax.compare(RHS) == APFloat::cmpLessThan) {  // smax < 13123.0
@@ -2900,7 +2900,7 @@
   } else {
     // If the RHS value is > UnsignedMax, fold the comparison. This handles
     // +INF and large values.
-    APFloat UMax(RHS.getSemantics(), APFloat::fcZero, false);
+    APFloat UMax(RHS.getSemantics());
     UMax.convertFromAPInt(APInt::getMaxValue(IntWidth), false,
                           APFloat::rmNearestTiesToEven);
     if (UMax.compare(RHS) == APFloat::cmpLessThan) {  // umax < 13123.0
@@ -2913,7 +2913,7 @@
 
   if (!LHSUnsigned) {
     // See if the RHS value is < SignedMin.
-    APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
+    APFloat SMin(RHS.getSemantics());
     SMin.convertFromAPInt(APInt::getSignedMinValue(IntWidth), true,
                           APFloat::rmNearestTiesToEven);
     if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // smin > 12312.0
@@ -2924,7 +2924,7 @@
     }
   } else {
     // See if the RHS value is < UnsignedMin.
-    APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
+    APFloat SMin(RHS.getSemantics());
     SMin.convertFromAPInt(APInt::getMinValue(IntWidth), true,
                           APFloat::rmNearestTiesToEven);
     if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // umin > 12312.0