[llvm] [InstCombine] Fold length-one memset with variable fillFold length-one memset with variable fill (PR #217224)

[via llvm-commits]

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@@ -0,0 +1,66 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
+
+declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg)
+declare void @llvm.memset.p1.i64(ptr addrspace(1) nocapture writeonly, i8, i64, i1 immarg)
+declare void @llvm.memset.element.unordered.atomic.p0.i64(ptr nocapture writeonly, i8, i64, i32 immarg)
+
+define void @variable_fill_len1(ptr %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len1(
+; CHECK-SAME: ptr [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    store i8 [[VALUE]], ptr [[DST]], align 1
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.p0.i64(ptr align 1 %dst, i8 %value, i64 1, i1 false)
+  ret void
+}
+
+define void @variable_fill_len1_volatile(ptr %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len1_volatile(
+; CHECK-SAME: ptr [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr align 1 [[DST]], i8 [[VALUE]], i64 1, i1 true)
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.p0.i64(ptr align 1 %dst, i8 %value, i64 1, i1 true)
+  ret void
+}
+
+define void @variable_fill_len1_align8(ptr %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len1_align8(
+; CHECK-SAME: ptr [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    store i8 [[VALUE]], ptr [[DST]], align 8
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.p0.i64(ptr align 8 %dst, i8 %value, i64 1, i1 false)
+  ret void
+}
+
+define void @variable_fill_len1_addrspace(ptr addrspace(1) %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len1_addrspace(
+; CHECK-SAME: ptr addrspace(1) [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    store i8 [[VALUE]], ptr addrspace(1) [[DST]], align 1
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.p1.i64(ptr addrspace(1) align 1 %dst, i8 %value, i64 1, i1 false)
+  ret void
+}
+
+define void @variable_fill_len1_atomic(ptr %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len1_atomic(
+; CHECK-SAME: ptr [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    store atomic i8 [[VALUE]], ptr [[DST]] unordered, align 1
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.element.unordered.atomic.p0.i64(ptr align 1 %dst, i8 %value, i64 1, i32 1)
+  ret void
+}
+
+define void @variable_fill_len2(ptr %dst, i8 %value) {
+; CHECK-LABEL: define void @variable_fill_len2(
+; CHECK-SAME: ptr [[DST:%.*]], i8 [[VALUE:%.*]]) {
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(2) [[DST]], i8 [[VALUE]], i64 2, i1 false)
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.memset.p0.i64(ptr align 1 %dst, i8 %value, i64 2, i1 false)
+  ret void
+}
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hsnaveen2u wrote:

Done. I added a length-one llvm.experimental.memset.pattern test and regenerated the checks using update_test_checks.py

https://github.com/llvm/llvm-project/pull/217224