SIL: Do not use -1 to construct a 1-bit llvm::APInt

A -1 truncated to 1 bit is just 1, so stop overcomplicating things here.

Author: AnthonyLatsis

lib/SILGen/SILGenAvailability.cpp

@@ -67,12 +67,12 @@ static SILValue emitAvailabilityCheck(SILGenFunction &SGF, SILLocation loc,
   SILValue result =
       B.createApply(loc, availabilityGTEFn, SubstitutionMap(), silArgs);
 
-  // If this is an unavailability check, invert the result using xor with -1.
+  // If this is an unavailability check, invert the result using 1-bit xor
+  // with 1.
   if (query.isUnavailability()) {
     SILType i1 = SILType::getBuiltinIntegerType(1, ctx);
-    SILValue minusOne = B.createIntegerLiteral(loc, i1, -1);
-    result =
-        B.createBuiltinBinaryFunction(loc, "xor", i1, i1, {result, minusOne});
+    SILValue one = B.createIntegerLiteral(loc, i1, 1);
+    result = B.createBuiltinBinaryFunction(loc, "xor", i1, i1, {result, one});
   }
 
   return result;

lib/SILOptimizer/LoopTransforms/BoundsCheckOpts.cpp

@@ -573,7 +573,7 @@ static SILValue getSub(SILLocation Loc, SILValue Val, unsigned SubVal,
   SmallVector<SILValue, 4> Args(1, Val);
   Args.push_back(B.createIntegerLiteral(Loc, Val->getType(), SubVal));
   Args.push_back(B.createIntegerLiteral(
-      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), -1));
+      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), 1));
 
   auto *AI = B.createBuiltinBinaryFunctionWithOverflow(
       Loc, "ssub_with_overflow", Args);
@@ -585,7 +585,7 @@ static SILValue getAdd(SILLocation Loc, SILValue Val, unsigned AddVal,
   SmallVector<SILValue, 4> Args(1, Val);
   Args.push_back(B.createIntegerLiteral(Loc, Val->getType(), AddVal));
   Args.push_back(B.createIntegerLiteral(
-      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), -1));
+      Loc, SILType::getBuiltinIntegerType(1, B.getASTContext()), 1));
 
   auto *AI = B.createBuiltinBinaryFunctionWithOverflow(
       Loc, "sadd_with_overflow", Args);