[PATCH 11/27] [noalias] D9379: llvm.noalias and ValueTracking

[jeroen.dobbelaere]

Summary

This is part of the series started by D68484.

Rebase of:

• D9379: llvm.noalias - don't interfere with llvm.assume
• D9398: llvm.noalias - GetUnderlyingObjects to optionally collect noalias calls

And adapted for full restrict.

[jeroen.dobbelaere]

Rebased

[jeroen.dobbelaere]

Rebased to c06b7e2ab5167ad031745a706204abed1aefd823 (July 14, 2020)

[jeroen.dobbelaere]

Rebased to 9fb46a452d4e5666828c95610ceac8dcd9e4ce16 (September 7, 2020)

[jeroen.dobbelaere]

Rebased to f8dbd61074176bae92ec360a093ac7bc498c9321.

llvm/lib/Analysis/ValueTracking.cpp

if (Function *F = CI->getCalledFunction())
       case Intrinsic::sideeffect:
       case Intrinsic::dbg_declare:
       case Intrinsic::dbg_value:
       case Intrinsic::dbg_label:
       case Intrinsic::invariant_start:
       case Intrinsic::invariant_end:
       case Intrinsic::lifetime_start:
       case Intrinsic::lifetime_end:
+      case Intrinsic::noalias:
       case Intrinsic::objectsize:
       case Intrinsic::ptr_annotation:
       case Intrinsic::var_annotation:
         return true;
       }
 
   return false;
 }

llvm/test/Transforms/InstCombine/assume.ll

;
   %t2 = bitcast <4 x i8> %shuf to i32
   %t3 = icmp ult i32 %t2, 65536
   call void @llvm.assume(i1 %t3)
   ret i32 %t2
 }
 
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 
+define i1 @nonnull5(i32** %a) {
+entry:
+  %load = load i32*, i32** %a
+  ;; This call cannot actually trap, and so should not disrupt the assume.
+  %v = call i32* @llvm.noalias.p0i32(i32* %load, metadata !1)
+  %cmp = icmp ne i32* %load, null
+  tail call void @llvm.assume(i1 %cmp)
+  %q = bitcast i32** %a to i32*
+  %rval = icmp eq i32* %v, %q
+  ret i1 %rval
+
+; CHECK-LABEL: @nonnull5
+; CHECK: !nonnull
+; CHECK-NOT: call void @llvm.assume
+}
+
+declare i32* @llvm.noalias.p0i32(i32*, metadata) nounwind
+
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!5, !6, !7, !8}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "Me", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: null, retainedTypes: null, imports: null)
 !1 = !DILocalVariable(name: "", arg: 1, scope: !2, file: null, line: 1, type: null)
 !2 = distinct !DISubprogram(name: "debug", linkageName: "debug", scope: null, file: null, line: 0, type: null, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
 !3 = !DIFile(filename: "consecutive-fences.ll", directory: "")
 !5 = !{i32 2, !"Dwarf Version", i32 4}
 !6 = !{i32 2, !"Debug Info Version", i32 3}
 !7 = !{i32 1, !"wchar_size", i32 4}
 !8 = !{i32 7, !"PIC Level", i32 2}
 !9 = !DILocation(line: 0, column: 0, scope: !2)
+!10 = !{!10, !"some domain"}
+!11 = !{!11, !10, !"some scope"}
 
 
 attributes #0 = { nounwind uwtable }
 attributes #1 = { nounwind }