[llvm] 3b219cf - [LV] Add register pressure test for #164124.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2025-11-08T21:59:38Z
New Revision: 3b219cf42ac4970fc01a4e9d4b428d9689e13f78

URL: https://github.com/llvm/llvm-project/commit/3b219cf42ac4970fc01a4e9d4b428d9689e13f78
DIFF: https://github.com/llvm/llvm-project/commit/3b219cf42ac4970fc01a4e9d4b428d9689e13f78.diff

LOG: [LV] Add register pressure test for #164124.

Add extra test for https://github.com/llvm/llvm-project/pull/164124

Added: 
    

Modified: 
    llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll b/llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll
index 70685c1c3fe12..d4fb3d70c538d 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/reg-usage.ll
@@ -248,3 +248,30 @@ exit:                                        ; preds = %for.body
   %result = add nsw i32 %result0, %result1
   ret i32 %result
 }
+
+define i64 @loop_reduction_and_store_last_element(ptr %src, ptr writeonly %dst) {
+; CHECK-LABEL: LV: Checking a loop in 'loop_reduction_and_store_last_element'
+; CHECK:       LV(REG): VF = 16
+; CHECK-NEXT:  LV(REG): Found max usage: 2 item
+; CHECK-NEXT:  LV(REG): RegisterClass: Generic::ScalarRC, 2 registers
+; CHECK-NEXT:  LV(REG): RegisterClass: Generic::VectorRC, 16 registers
+; CHECK-NEXT:  LV(REG): Found invariant usage: 1 item
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 1, %entry ], [ %iv.next, %loop ]
+  %red = phi i64 [ 0, %entry ], [ %red.next, %loop ]
+  %ptr = phi ptr [ %src, %entry ], [ %ptr.next, %loop ]
+  %iv.next = add nuw i32 %iv, 1
+  %ptr.next = getelementptr i8, ptr %ptr, i64 1
+  store ptr %ptr, ptr %dst, align 8
+  %val = load i8, ptr %ptr, align 1
+  %val.ext = zext i8 %val to i64
+  %red.next = or i64 %red, %val.ext
+  %ec = icmp eq i32 %iv.next, 1000
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret i64 %red.next
+}