AMDGPU: Add subtarget features for minimum3/maximum3 instructions (#116308)

gfx12 and gfx950 managed to produce 3 different permutations of this feature.
gfx12 supports f32 and f16, and gfx950 supports f32 and v2f16.

Author: arsenm

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -137,6 +137,18 @@ def FeatureFmaMixInsts : SubtargetFeature<"fma-mix-insts",
   "Has v_fma_mix_f32, v_fma_mixlo_f16, v_fma_mixhi_f16 instructions"
 >;
 
+def FeatureMinimum3Maximum3F32 : SubtargetFeature<"minimum3-maximum3-f32",
+  "HasMinimum3Maximum3F32",
+  "true",
+  "Has v_minimum3_f32 and v_maximum3_f32 instructions"
+>;
+
+def FeatureMinimum3Maximum3F16 : SubtargetFeature<"minimum3-maximum3-f16",
+  "HasMinimum3Maximum3F16",
+  "true",
+  "Has v_minimum3_f16 and v_maximum3_f16 instructions"
+>;
+
 def FeatureSupportsXNACK : SubtargetFeature<"xnack-support",
   "SupportsXNACK",
   "true",
@@ -1263,6 +1275,7 @@ def FeatureGFX12 : GCNSubtargetFeatureGeneration<"GFX12",
    FeatureUnalignedDSAccess, FeatureTrue16BitInsts,
    FeatureDefaultComponentBroadcast, FeatureMaxHardClauseLength32,
    FeatureAtomicFMinFMaxF32GlobalInsts, FeatureAtomicFMinFMaxF32FlatInsts,
+   FeatureMinimum3Maximum3F32, FeatureMinimum3Maximum3F16,
    FeatureAgentScopeFineGrainedRemoteMemoryAtomics
   ]
 >;
@@ -2005,6 +2018,15 @@ def isGFX12Plus :
   Predicate<"Subtarget->getGeneration() >= AMDGPUSubtarget::GFX12">,
   AssemblerPredicate<(all_of FeatureGFX12Insts)>;
 
+def HasMinimum3Maximum3F32 :
+  Predicate<"Subtarget->hasMinimum3Maximum3F32()">,
+  AssemblerPredicate<(all_of FeatureMinimum3Maximum3F32)>;
+
+def HasMinimum3Maximum3F16 :
+  Predicate<"Subtarget->hasMinimum3Maximum3F16()">,
+  AssemblerPredicate<(all_of FeatureMinimum3Maximum3F16)>;
+
+
 def HasFlatAddressSpace : Predicate<"Subtarget->hasFlatAddressSpace()">,
   AssemblerPredicate<(all_of FeatureFlatAddressSpace)>;
 

llvm/lib/Target/AMDGPU/GCNSubtarget.h

@@ -242,7 +242,8 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   bool HasForceStoreSC0SC1 = false;
   bool HasRequiredExportPriority = false;
   bool HasVmemWriteVgprInOrder = false;
-
+  bool HasMinimum3Maximum3F32 = false;
+  bool HasMinimum3Maximum3F16 = false;
   bool RequiresCOV6 = false;
 
   // Dummy feature to use for assembler in tablegen.
@@ -1307,6 +1308,14 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   /// \returns true if the target has instructions with xf32 format support.
   bool hasXF32Insts() const { return HasXF32Insts; }
 
+  bool hasMinimum3Maximum3F32() const {
+    return HasMinimum3Maximum3F32;
+  }
+
+  bool hasMinimum3Maximum3F16() const {
+    return HasMinimum3Maximum3F16;
+  }
+
   /// \returns The maximum number of instructions that can be enclosed in an
   /// S_CLAUSE on the given subtarget, or 0 for targets that do not support that
   /// instruction.

llvm/lib/Target/AMDGPU/VOP3Instructions.td

@@ -226,7 +226,7 @@ let mayRaiseFPException = 0 in {
   defm V_MED3_F32 : VOP3Inst <"v_med3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfmed3>;
 } // End mayRaiseFPException = 0
 
-let SubtargetPredicate = isGFX12Plus, ReadsModeReg = 0 in {
+let SubtargetPredicate = HasMinimum3Maximum3F32, ReadsModeReg = 0 in {
   defm V_MINIMUM3_F32 : VOP3Inst <"v_minimum3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfminimum3>;
   defm V_MAXIMUM3_F32 : VOP3Inst <"v_maximum3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfmaximum3>;
 } // End SubtargetPredicate = isGFX12Plus, ReadsModeReg = 0
@@ -625,7 +625,7 @@ defm V_MAX3_F16 : VOP3Inst <"v_max3_f16", VOP3_Profile<VOP_F16_F16_F16_F16, VOP3
 defm V_MAX3_I16 : VOP3Inst <"v_max3_i16", VOP3_Profile<VOP_I16_I16_I16_I16, VOP3_OPSEL>, AMDGPUsmax3>;
 defm V_MAX3_U16 : VOP3Inst <"v_max3_u16", VOP3_Profile<VOP_I16_I16_I16_I16, VOP3_OPSEL>, AMDGPUumax3>;
 
-let SubtargetPredicate = isGFX12Plus, ReadsModeReg = 0 in {
+let SubtargetPredicate = HasMinimum3Maximum3F16, ReadsModeReg = 0 in {
   defm V_MINIMUM3_F16 : VOP3Inst <"v_minimum3_f16", VOP3_Profile<VOP_F16_F16_F16_F16, VOP3_OPSEL>, AMDGPUfminimum3>;
   defm V_MAXIMUM3_F16 : VOP3Inst <"v_maximum3_f16", VOP3_Profile<VOP_F16_F16_F16_F16, VOP3_OPSEL>, AMDGPUfmaximum3>;
 } // End SubtargetPredicate = isGFX12Plus, ReadsModeReg = 0