[llvm] [Hexagon] Fix shift value when folding shl DAG node (PR #83853)

[Ikhlas Ajbar via llvm-commits]

================
@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=hexagon-unknown-elf < %s | FileCheck %s
+
+; In ISelLowering, when folding nodes (or (shl xx, s), (zext y))
+; to (COMBINE (shl xx, s-32), y) where s >= 32,
+; check that resulting shift value does not create an undef
+
+
+target datalayout = "e-m:e-p:32:32:32-a:0-n16:32-i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048"
+target triple = "hexagon"
+
+; Function Attrs: nofree nosync nounwind memory(readwrite, inaccessiblemem: none)
+define dso_local void @foo(i64* nocapture noundef %buf, i32 %a, i32 %b) local_unnamed_addr #0 {
+; CHECK-LABEL: foo:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    {
+; CHECK-NEXT:     r2 = addasl(r2,r1,#1)
+; CHECK-NEXT:     r3 = asl(r1,#1)
+; CHECK-NEXT:    }
+; CHECK-NEXT:    {
+; CHECK-NEXT:     r2 = addasl(r2,r1,#1)
+; CHECK-NEXT:    }
+; CHECK-NEXT:    {
+; CHECK-NEXT:     jumpr r31
+; CHECK-NEXT:     memd(r0+#8) = r3:2
+; CHECK-NEXT:    }
+entry:
+  %arrayidx = getelementptr inbounds i64, i64* %buf, i32 1
+  %add0 = shl nsw i32 %a, 1
+  %add1 = add nsw i32 %add0, %b
+  %add2 = add nsw i32 %add1, %add0
+  %ext0 = zext i32 %add0 to i64
+  %shift0 = shl nuw i64 %ext0, 32
+  %ext1 = zext i32 %add2 to i64
+  %or0 = or i64 %shift0, %ext1
+  store i64 %or0, i64* %arrayidx, align 8, !tbaa !2
+  ret void
+}
+
+attributes #0 = { nofree nosync nounwind memory(readwrite, inaccessiblemem: none) "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="hexagonv71" "target-features"="+v71,-long-calls" }
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 7, !"frame-pointer", i32 2}
+!2 = !{!3, !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
----------------
iajbar wrote:

Does the test need to have:
attributes #0 = { nofree nosync nounwind memory(readwrite, inaccessiblemem: none) "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="hexagonv71" "target-features"="+v71,-long-calls" }

!llvm.module.flags = !{!0, !1}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 7, !"frame-pointer", i32 2}
!2 = !{!3, !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}

I think you can remove it. 

https://github.com/llvm/llvm-project/pull/83853