[Attributes] Merge calls to getFnAttribute/hasFnAttribute using Attribute::isValid. NFC

Rather than calling hasFnAttribute and then calling getFnAttribute
if the attribute exists, its better to just call getFnAttribute and
then check if we got a valid attribute back.

Author: topperc

llvm/lib/IR/Attributes.cpp

@@ -1937,21 +1937,19 @@ static void adjustCallerStackProbes(Function &Caller, const Function &Callee) {
 /// that is no larger.
 static void
 adjustCallerStackProbeSize(Function &Caller, const Function &Callee) {
-  if (Callee.hasFnAttribute("stack-probe-size")) {
-    uint64_t CalleeStackProbeSize;
-    Callee.getFnAttribute("stack-probe-size")
-          .getValueAsString()
-          .getAsInteger(0, CalleeStackProbeSize);
-    if (Caller.hasFnAttribute("stack-probe-size")) {
-      uint64_t CallerStackProbeSize;
-      Caller.getFnAttribute("stack-probe-size")
-            .getValueAsString()
-            .getAsInteger(0, CallerStackProbeSize);
+  Attribute CalleeAttr = Callee.getFnAttribute("stack-probe-size");
+  if (CalleeAttr.isValid()) {
+    Attribute CallerAttr = Caller.getFnAttribute("stack-probe-size");
+    if (CallerAttr.isValid()) {
+      uint64_t CallerStackProbeSize, CalleeStackProbeSize;
+      CallerAttr.getValueAsString().getAsInteger(0, CallerStackProbeSize);
+      CalleeAttr.getValueAsString().getAsInteger(0, CalleeStackProbeSize);
+
       if (CallerStackProbeSize > CalleeStackProbeSize) {
-        Caller.addFnAttr(Callee.getFnAttribute("stack-probe-size"));
+        Caller.addFnAttr(CalleeAttr);
       }
     } else {
-      Caller.addFnAttr(Callee.getFnAttribute("stack-probe-size"));
+      Caller.addFnAttr(CalleeAttr);
     }
   }
 }
@@ -1967,18 +1965,15 @@ adjustCallerStackProbeSize(Function &Caller, const Function &Callee) {
 /// handled as part of inline cost analysis.
 static void
 adjustMinLegalVectorWidth(Function &Caller, const Function &Callee) {
-  if (Caller.hasFnAttribute("min-legal-vector-width")) {
-    if (Callee.hasFnAttribute("min-legal-vector-width")) {
-      uint64_t CallerVectorWidth;
-      Caller.getFnAttribute("min-legal-vector-width")
-            .getValueAsString()
-            .getAsInteger(0, CallerVectorWidth);
-      uint64_t CalleeVectorWidth;
-      Callee.getFnAttribute("min-legal-vector-width")
-            .getValueAsString()
-            .getAsInteger(0, CalleeVectorWidth);
+  Attribute CallerAttr = Caller.getFnAttribute("min-legal-vector-width");
+  if (CallerAttr.isValid()) {
+    Attribute CalleeAttr = Callee.getFnAttribute("min-legal-vector-width");
+    if (CalleeAttr.isValid()) {
+      uint64_t CallerVectorWidth, CalleeVectorWidth;
+      CallerAttr.getValueAsString().getAsInteger(0, CallerVectorWidth);
+      CalleeAttr.getValueAsString().getAsInteger(0, CalleeVectorWidth);
       if (CallerVectorWidth < CalleeVectorWidth)
-        Caller.addFnAttr(Callee.getFnAttribute("min-legal-vector-width"));
+        Caller.addFnAttr(CalleeAttr);
     } else {
       // If the callee doesn't have the attribute then we don't know anything
       // and must drop the attribute from the caller.