Fix comments, add test case for multiple extensions

Author: domin144

clang/test/Driver/print-multi-selection-flags.c

@@ -40,6 +40,11 @@
 // CHECK-V8_1_FP_DP: -mfloat-abi=hard
 // CHECK-V8_1_FP_DP: -mfpu=fp-armv8-fullfp16-d16
 
+// RUN: %clang -print-multi-flags-experimental --target=arm-none-eabihf -march=armv8.1m.main+nofp+fp+nofp.dp | FileCheck --check-prefix=CHECK-V8_1_NO_FP_DP %s
+// CHECK-V8_1_NO_FP_DP: -march=thumbv8.1m.main{{.*}}
+// CHECK-V8_1_NO_FP_DP: -mfloat-abi=hard
+// CHECK-V8_1_NO_FP_DP: -mfpu=fp-armv8-fullfp16-sp-d16
+
 // RUN: %clang -print-multi-flags-experimental --target=arm-none-eabihf -mcpu=cortex-m85+nofp.dp | FileCheck --check-prefix=CHECK-M85_NO_FP_DP %s
 // CHECK-M85_NO_FP_DP: -march=thumbv8.1m.main{{.*}}
 // CHECK-M85_NO_FP_DP: -mfloat-abi=hard

llvm/lib/TargetParser/ARMTargetParser.cpp

@@ -371,6 +371,8 @@ static ARM::FPUKind findDoublePrecisionFPU(ARM::FPUKind InputFPUKind) {
 
   const ARM::FPUName &InputFPU = ARM::FPUNames[InputFPUKind];
 
+  // If the input FPU already supports double-precision, then there
+  // isn't any different FPU we can return here.
   if (ARM::isDoublePrecision(InputFPU.Restriction))
     return InputFPUKind;
 
@@ -396,9 +398,8 @@ static ARM::FPUKind findSinglePrecisionFPU(ARM::FPUKind InputFPUKind) {
 
   const ARM::FPUName &InputFPU = ARM::FPUNames[InputFPUKind];
 
-  // If the input FPU already supports double-precision, then there
+  // If the input FPU already is single-precision only, then there
   // isn't any different FPU we can return here.
-  //
   if (!ARM::isDoublePrecision(InputFPU.Restriction))
     return InputFPUKind;