More noalias optimizations (#2161)

EnzymeAD · Nov 11, 2024 · 4a0ebd8 · 4a0ebd8
1 parent f8a4892
commit 4a0ebd8
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diff --git a/enzyme/Enzyme/JLInstSimplify.cpp b/enzyme/Enzyme/JLInstSimplify.cpp
@@ -197,6 +197,31 @@ bool jlInstSimplify(llvm::Function &F, TargetLibraryInfo &TLI,
           changed = true;
           continue;
         }
+
+        {
+          bool noalias_from_capture = false;
+          for (int i = 0; i < 2; i++) {
+            Value *start = (i == 0) ? lhs : rhs;
+            Value *end = (i == 0) ? rhs : lhs;
+            if (isNoAlias(start)) {
+              if (auto endi = dyn_cast<Instruction>(end)) {
+                if (notCapturedBefore(start, endi)) {
+                  noalias_from_capture = true;
+                  break;
+                }
+              }
+            }
+          }
+          if (noalias_from_capture) {
+            auto repval = ICmpInst::isTrueWhenEqual(pred)
+                              ? ConstantInt::get(I.getType(), 0)
+                              : ConstantInt::get(I.getType(), 1);
+            I.replaceAllUsesWith(repval);
+            changed = true;
+            continue;
+          }
+        }
+
         auto llhs = dyn_cast<LoadInst>(lhs);
         auto lrhs = dyn_cast<LoadInst>(rhs);
         if (llhs && lrhs && isa<PointerType>(llhs->getType()) &&

diff --git a/enzyme/test/Enzyme/JLSimplify/alloc2d.ll b/enzyme/test/Enzyme/JLSimplify/alloc2d.ll
@@ -0,0 +1,25 @@
+; RUN: if [ %llvmver -lt 16 ]; then %opt < %s %loadEnzyme -jl-inst-simplify -S | FileCheck %s; fi
+; RUN: %opt < %s %newLoadEnzyme -passes="jl-inst-simplify" -S | FileCheck %s
+
+declare noalias nonnull {} addrspace(10)* @ijl_alloc_array_2d({} addrspace(10)*, i64, i64) local_unnamed_addr #0
+
+declare fastcc nonnull {} addrspace(10)* @a20()
+
+define i1 @chillin()  {
+bb:
+  %i = call fastcc nonnull {} addrspace(10)* @a20()
+  %i2 = call noalias nonnull {} addrspace(10)* @ijl_alloc_array_2d({} addrspace(10)* addrspacecast ({}* inttoptr (i64 139753406594768 to {}*) to {} addrspace(10)*), i64 5, i64 6)
+  %i3 = icmp eq {} addrspace(10)* %i2, %i
+  ret i1 %i3
+}
+
+attributes #0 = { inaccessiblememonly mustprogress nofree nounwind willreturn }
+
+
+; CHECK: define i1 @chillin() {
+; CHECK-NEXT: bb:
+; CHECK-NEXT:   %i = call fastcc nonnull {} addrspace(10)* @a20()
+; CHECK-NEXT:   %i2 = call noalias nonnull {} addrspace(10)* @ijl_alloc_array_2d({} addrspace(10)* addrspacecast ({}* inttoptr (i64 139753406594768 to {}*) to {} addrspace(10)*), i64 5, i64 6)
+; CHECK-NEXT:   %i3 = icmp eq {} addrspace(10)* %i2, %i
+; CHECK-NEXT:   ret i1 false
+; CHECK-NEXT: }