[PATCH] D144298: [Local][SimplifyCFG] Handle !nontemporal in combineMetadata

[Daniel Woodworth via Phabricator via llvm-commits]

dwoodwor-intel created this revision.
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SimplifyCFG currently drops !nontemporal metadata when sinking common instructions. With this change, SimplifyCFG and similar transforms will preserve !nontemporal metadata as long as it is set on both original instructions.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D144298

Files:
  llvm/lib/Transforms/Utils/Local.cpp
  llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll


Index: llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
+++ llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
@@ -1559,3 +1559,47 @@
 end:
   ret void
 }
+
+define void @nontemporal(ptr %ptr, i1 %cond) {
+; CHECK-LABEL: @nontemporal(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    store i64 0, ptr [[PTR:%.*]], align 8, !nontemporal !7
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 %cond, label %if.then, label %if.else
+
+if.then:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.else:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+define void @nontemporal_mismatch(ptr %ptr, i1 %cond) {
+; CHECK-LABEL: @nontemporal_mismatch(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    store i64 0, ptr [[PTR:%.*]], align 8
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 %cond, label %if.then, label %if.else
+
+if.then:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.else:
+  store i64 0, ptr %ptr, align 8
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+!12 = !{i32 1}
Index: llvm/lib/Transforms/Utils/Local.cpp
===================================================================
--- llvm/lib/Transforms/Utils/Local.cpp
+++ llvm/lib/Transforms/Utils/Local.cpp
@@ -2724,6 +2724,10 @@
         if (DoesKMove)
           K->setMetadata(Kind, JMD);
         break;
+      case LLVMContext::MD_nontemporal:
+        // Preserve !nontemporal if it is present on both instructions.
+        K->setMetadata(Kind, JMD);
+        break;
     }
   }
   // Set !invariant.group from J if J has it. If both instructions have it
@@ -2746,7 +2750,8 @@
       LLVMContext::MD_invariant_group, LLVMContext::MD_align,
       LLVMContext::MD_dereferenceable,
       LLVMContext::MD_dereferenceable_or_null,
-      LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index};
+      LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index,
+      LLVMContext::MD_nontemporal};
   combineMetadata(K, J, KnownIDs, KDominatesJ);
 }
 
@@ -2831,7 +2836,7 @@
       LLVMContext::MD_fpmath,          LLVMContext::MD_invariant_load,
       LLVMContext::MD_invariant_group, LLVMContext::MD_nonnull,
       LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index,
-      LLVMContext::MD_noundef};
+      LLVMContext::MD_noundef,         LLVMContext::MD_nontemporal};
   combineMetadata(ReplInst, I, KnownIDs, false);
 }
 


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