[AMDGPU] Refactor unit test. NFC (#82976)

I'm about to add more tests here (downstream for now).

Change-Id: Ibd5edb398f544c90e6e8b5e49b1777a407f0594a

Author: rovka

llvm/unittests/Target/AMDGPU/AMDGPUUnitTests.cpp

@@ -92,9 +92,23 @@ static const std::pair<StringRef, StringRef>
   W32FS = {"+wavefrontsize32", "w32"},
   W64FS = {"+wavefrontsize64", "w64"};
 
-static void testGPRLimits(
-    const char *RegName, bool TestW32W64,
-    std::function<bool(std::stringstream &, unsigned, GCNSubtarget &)> test) {
+using TestFuncTy =
+    function_ref<bool(std::stringstream &, unsigned, const GCNSubtarget &)>;
+
+static bool testAndRecord(std::stringstream &Table, const GCNSubtarget &ST,
+                          TestFuncTy test) {
+  bool Success = true;
+  unsigned MaxOcc = ST.getMaxWavesPerEU();
+  for (unsigned Occ = MaxOcc; Occ > 0; --Occ) {
+    Table << std::right << std::setw(3) << Occ << "    ";
+    Success = test(Table, Occ, ST) && Success;
+    Table << '\n';
+  }
+  return Success;
+}
+
+static void testGPRLimits(const char *RegName, bool TestW32W64,
+                          TestFuncTy test) {
   SmallVector<StringRef> CPUs;
   AMDGPU::fillValidArchListAMDGCN(CPUs);
 
@@ -117,13 +131,7 @@ static void testGPRLimits(
         FS = &W32FS;
 
       std::stringstream Table;
-      bool Success = true;
-      unsigned MaxOcc = ST.getMaxWavesPerEU();
-      for (unsigned Occ = MaxOcc; Occ > 0; --Occ) {
-        Table << std::right << std::setw(3) << Occ << "    ";
-        Success = test(Table, Occ, ST) && Success;
-        Table << '\n';
-      }
+      bool Success = testAndRecord(Table, ST, test);
       if (!Success || PrintCpuRegLimits)
         TablePerCPUs[Table.str()].push_back((CanonCPUName + FS->second).str());
 
@@ -145,13 +153,14 @@ static void testGPRLimits(
 }
 
 TEST(AMDGPU, TestVGPRLimitsPerOccupancy) {
-  testGPRLimits("VGPR", true, [](std::stringstream &OS, unsigned Occ,
-                                 GCNSubtarget &ST) {
+  auto test = [](std::stringstream &OS, unsigned Occ, const GCNSubtarget &ST) {
     unsigned MaxVGPRNum = ST.getAddressableNumVGPRs();
     return checkMinMax(
         OS, Occ, ST.getOccupancyWithNumVGPRs(MaxVGPRNum), ST.getMaxWavesPerEU(),
         [&](unsigned NumGPRs) { return ST.getOccupancyWithNumVGPRs(NumGPRs); },
         [&](unsigned Occ) { return ST.getMinNumVGPRs(Occ); },
         [&](unsigned Occ) { return ST.getMaxNumVGPRs(Occ); });
-  });
+  };
+
+  testGPRLimits("VGPR", true, test);
 }