Remove assert and std::min

It's actually possible to hit the assert on a valid IR if both
amdgpu-num-sgprs and amdgpu-num-vgprs are defined and have very low
values. It's also unnecessary to take the minimum between the spilling
and increase occupancy targets, which will be necessarily higher and
therefore automatically satisfied even when these attributes are
defined.

Author: lucas-rami

llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp

@@ -1716,19 +1716,14 @@ bool PreRARematStage::canIncreaseOccupancyOrReduceSpill() {
     TargetOcc = std::nullopt;
   } else {
     // There is no spilling and room to improve occupancy; set up "increased
-    // occupancy targets" for all regions. We further restrict the SGPR/VGPR
-    // limits for increasing occupancy by the "spilling limits" since the latter
-    // may end up smaller due to "amdgpu-num-sgpr" / "amdgpu-num-vgpr"
-    // attributes.
+    // occupancy targets" for all regions.
     TargetOcc = DAG.MinOccupancy + 1;
     unsigned VGPRBlockSize =
         MF.getInfo<SIMachineFunctionInfo>()->getDynamicVGPRBlockSize();
-    MaxSGPRs = std::min(MaxSGPRs, ST.getMaxNumSGPRs(*TargetOcc, false));
-    MaxVGPRs = std::min(MaxVGPRs, ST.getMaxNumVGPRs(*TargetOcc, VGPRBlockSize));
+    MaxSGPRs = ST.getMaxNumSGPRs(*TargetOcc, false);
+    MaxVGPRs = ST.getMaxNumVGPRs(*TargetOcc, VGPRBlockSize);
     ResetTargetRegions();
-    assert(!OptRegions.empty() && "there should be at least one target region");
   }
-
   REMAT_DEBUG({
     dbgs() << "Analyzing ";
     MF.getFunction().printAsOperand(dbgs(), false);