AMDGPU: Stop handling legacy amdgpu-unsafe-fp-atomics attribute

This is now autoupgraded to annotate atomicrmw instructions in
old bitcode.

Author: arsenm

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -16123,14 +16123,7 @@ static bool globalMemoryFPAtomicIsLegal(const GCNSubtarget &Subtarget,
   } else if (Subtarget.supportsAgentScopeFineGrainedRemoteMemoryAtomics())
     return true;
 
-  if (RMW->hasMetadata("amdgpu.no.fine.grained.memory"))
-    return true;
-
-  // TODO: Auto-upgrade this attribute to the metadata in function body and stop
-  // checking it.
-  return RMW->getFunction()
-      ->getFnAttribute("amdgpu-unsafe-fp-atomics")
-      .getValueAsBool();
+  return RMW->hasMetadata("amdgpu.no.fine.grained.memory");
 }
 
 TargetLowering::AtomicExpansionKind

llvm/test/Transforms/AtomicExpand/AMDGPU/expand-atomic-mmra.ll

@@ -124,7 +124,7 @@ define i16 @test_cmpxchg_i16_global_agent_align4(ptr addrspace(1) %out, i16 %in,
   ret i16 %extract
 }
 
-define void @syncscope_workgroup_nortn(ptr %addr, float %val) #0 {
+define void @syncscope_workgroup_nortn(ptr %addr, float %val) {
 ; GFX90A-LABEL: define void @syncscope_workgroup_nortn(
 ; GFX90A-SAME: ptr [[ADDR:%.*]], float [[VAL:%.*]]) #[[ATTR1:[0-9]+]] {
 ; GFX90A-NEXT:    br label [[ATOMICRMW_CHECK_SHARED:%.*]]
@@ -159,7 +159,7 @@ define void @syncscope_workgroup_nortn(ptr %addr, float %val) #0 {
 ; GFX1100-NEXT:    [[RES:%.*]] = atomicrmw fadd ptr [[ADDR]], float [[VAL]] syncscope("workgroup") seq_cst, align 4, !mmra [[META0]]
 ; GFX1100-NEXT:    ret void
 ;
-  %res = atomicrmw fadd ptr %addr, float %val syncscope("workgroup") seq_cst, !mmra !2
+  %res = atomicrmw fadd ptr %addr, float %val syncscope("workgroup") seq_cst, !mmra !2, !amdgpu.no.fine.grained.memory !3, !amdgpu.ignore.denormal.mode !3
   ret void
 }
 
@@ -188,11 +188,10 @@ define i32 @atomic_load_global_align1(ptr addrspace(1) %ptr) {
   ret i32 %val
 }
 
-attributes #0 = { "amdgpu-unsafe-fp-atomics"="true" }
-
 !0 = !{!"foo", !"bar"}
 !1 = !{!"bux", !"baz"}
 !2 = !{!0, !1}
+!3 = !{}
 ;.
 ; GFX90A: [[META0]] = !{[[META1:![0-9]+]], [[META2:![0-9]+]]}
 ; GFX90A: [[META1]] = !{!"foo", !"bar"}