[llvm] 6fdcdbd - [MemCpyOpt] Avoid introducing UB, precommit tests (NFC)
Antonio Frighetto via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 30 01:10:05 PST 2026
Author: Antonio Frighetto
Date: 2026-01-30T10:09:07+01:00
New Revision: 6fdcdbded04905da5ddf00b8bccd71b4cbf1a461
URL: https://github.com/llvm/llvm-project/commit/6fdcdbded04905da5ddf00b8bccd71b4cbf1a461
DIFF: https://github.com/llvm/llvm-project/commit/6fdcdbded04905da5ddf00b8bccd71b4cbf1a461.diff
LOG: [MemCpyOpt] Avoid introducing UB, precommit tests (NFC)
Added:
Modified:
llvm/test/Transforms/MemCpyOpt/memset-memcpy-oversized.ll
Removed:
################################################################################
diff --git a/llvm/test/Transforms/MemCpyOpt/memset-memcpy-oversized.ll b/llvm/test/Transforms/MemCpyOpt/memset-memcpy-oversized.ll
index 2575d58dcac72..1371f2e4bbd16 100644
--- a/llvm/test/Transforms/MemCpyOpt/memset-memcpy-oversized.ll
+++ b/llvm/test/Transforms/MemCpyOpt/memset-memcpy-oversized.ll
@@ -152,13 +152,13 @@ define void @test_negative_offset_memset(ptr %result) {
; CHECK-LABEL: @test_negative_offset_memset(
; CHECK-NEXT: [[A1:%.*]] = alloca [16 x i8], align 8
; CHECK-NEXT: [[A:%.*]] = getelementptr i8, ptr [[A1]], i32 4
-; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 8 [[A]], i8 0, i64 12, i1 false)
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[A]], i8 0, i64 12, i1 false)
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[RESULT:%.*]], ptr align 8 [[A1]], i64 12, i1 false)
; CHECK-NEXT: ret void
;
%a = alloca [ 16 x i8 ], align 8
%b = getelementptr i8, ptr %a, i32 4
- call void @llvm.memset.p0.i64(ptr align 8 %b, i8 0, i64 12, i1 false)
+ call void @llvm.memset.p0.i64(ptr align 4 %b, i8 0, i64 12, i1 false)
call void @llvm.memcpy.p0.p0.i64(ptr %result, ptr align 8 %a, i64 12, i1 false)
ret void
}
@@ -174,7 +174,7 @@ define void @test_offset_memsetcpy(ptr %result) {
%a = alloca [ 16 x i8 ], align 8
%b = getelementptr i8, ptr %a, i32 4
call void @llvm.memset.p0.i64(ptr align 8 %a, i8 0, i64 12, i1 false)
- call void @llvm.memcpy.p0.p0.i64(ptr %result, ptr align 8 %b, i64 12, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %result, ptr align 4 %b, i64 12, i1 false)
ret void
}
@@ -183,18 +183,121 @@ define void @test_two_memset(ptr %result) {
; CHECK-NEXT: [[A:%.*]] = alloca [16 x i8], align 8
; CHECK-NEXT: [[B:%.*]] = getelementptr i8, ptr [[A]], i32 12
; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 8 [[A]], i8 0, i64 12, i1 false)
-; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 8 [[B]], i8 1, i64 4, i1 false)
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[B]], i8 1, i64 4, i1 false)
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[RESULT:%.*]], ptr align 8 [[A]], i64 16, i1 false)
; CHECK-NEXT: ret void
;
%a = alloca [ 16 x i8 ], align 8
%b = getelementptr i8, ptr %a, i32 12
call void @llvm.memset.p0.i64(ptr align 8 %a, i8 0, i64 12, i1 false)
- call void @llvm.memset.p0.i64(ptr align 8 %b, i8 1, i64 4, i1 false)
+ call void @llvm.memset.p0.i64(ptr align 4 %b, i8 1, i64 4, i1 false)
call void @llvm.memcpy.p0.p0.i64(ptr %result, ptr align 8 %a, i64 16, i1 false)
ret void
}
+; Allocate 26 bytes, memset 24 bytes starting from offset 2, memcpy out the whole area.
+define void @test_negative_offset_memset_2(ptr %out) {
+; CHECK-LABEL: @test_negative_offset_memset_2(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca <{ [2 x i8], i64, i64, i64 }>, align 8
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 2
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[OFFSET]], i8 0, i64 24, i1 false)
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[OUT:%.*]], ptr [[ALLOCA]], i64 26, i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca <{ [2 x i8], i64, i64, i64 }>
+ %offset = getelementptr i8, ptr %alloca, i64 2
+ call void @llvm.memset.p0.i64(ptr %offset, i8 0, i64 24, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %out, ptr %alloca, i64 26, i1 false)
+ ret void
+}
+
+; Allocate 20 bytes, memset the last 10 bytes, memcpy out the first 15 bytes,
+; meaning that only the last 5 bytes of the source are zeroed out.
+define void @test_negative_offset_memset_3(ptr %out) {
+; CHECK-LABEL: @test_negative_offset_memset_3(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [20 x i8], align 1
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 10
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[OFFSET]], i8 0, i64 10, i1 false)
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[OUT:%.*]], ptr [[ALLOCA]], i64 15, i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca [20 x i8]
+ %offset = getelementptr i8, ptr %alloca, i64 10
+ call void @llvm.memset.p0.i64(ptr %offset, i8 0, i64 10, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %out, ptr %alloca, i64 15, i1 false)
+ ret void
+}
+
+; Source/dest buffers have
diff erent alignment. Recompute it.
+define void @test_negative_offset_memset_
diff erent_alignment(ptr %out) {
+; CHECK-LABEL: @test_negative_offset_memset_
diff erent_alignment(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [20 x i8], align 1
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 4
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 1 [[OFFSET]], i8 0, i64 16, i1 false)
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 [[OUT:%.*]], ptr align 1 [[ALLOCA]], i64 20, i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca [20 x i8], align 1
+ %offset = getelementptr i8, ptr %alloca, i64 4
+ call void @llvm.memset.p0.i64(ptr align 1 %offset, i8 0, i64 16, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr align 8 %out, ptr align 1 %alloca, i64 20, i1 false)
+ ret void
+}
+
+; Allocate 20 bytes, memset the last 10 bytes, memcpy out the first 15 bytes
+; to %out - 10, meaning that only the first 5 bytes of %out will be zeroed out.
+define void @test_negative_offset_memset_and_negative_offset_memcpy_dest(ptr %out) {
+; CHECK-LABEL: @test_negative_offset_memset_and_negative_offset_memcpy_dest(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [20 x i8], align 1
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 10
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[OFFSET]], i8 0, i64 10, i1 false)
+; CHECK-NEXT: [[OFFSET_OUT:%.*]] = getelementptr i8, ptr [[OUT:%.*]], i64 -10
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[OFFSET_OUT]], ptr [[ALLOCA]], i64 15, i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca [20 x i8]
+ %offset = getelementptr i8, ptr %alloca, i64 10
+ call void @llvm.memset.p0.i64(ptr %offset, i8 0, i64 10, i1 false)
+ %offset_out = getelementptr i8, ptr %out, i64 -10
+ call void @llvm.memcpy.p0.p0.i64(ptr %offset_out, ptr %alloca, i64 15, i1 false)
+ ret void
+}
+
+; Negative tests.
+define void @test_negative_offset_memset_store_between(ptr %out) {
+; CHECK-LABEL: @test_negative_offset_memset_store_between(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca <{ [2 x i8], i64, i64, i64 }>, align 8
+; CHECK-NEXT: [[IDX_1:%.*]] = getelementptr inbounds nuw i8, ptr [[ALLOCA]], i64 1
+; CHECK-NEXT: store i8 1, ptr [[IDX_1]], align 1
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 2
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[OFFSET]], i8 0, i64 24, i1 false)
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[OUT:%.*]], ptr [[ALLOCA]], i64 26, i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca <{ [2 x i8], i64, i64, i64 }>
+ %idx_1 = getelementptr inbounds nuw i8, ptr %alloca, i64 1
+ store i8 1, ptr %idx_1
+ %offset = getelementptr i8, ptr %alloca, i64 2
+ call void @llvm.memset.p0.i64(ptr %offset, i8 0, i64 24, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %out, ptr %alloca, i64 26, i1 false)
+ ret void
+}
+
+define void @test_negative_offset_memset_variable_sized(ptr %out, i64 %sz1, i64 %sz2) {
+; CHECK-LABEL: @test_negative_offset_memset_variable_sized(
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca <{ [2 x i8], i64, i64, i64 }>, align 8
+; CHECK-NEXT: [[OFFSET:%.*]] = getelementptr i8, ptr [[ALLOCA]], i64 2
+; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr [[OFFSET]], i8 0, i64 [[SZ1:%.*]], i1 false)
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[OUT:%.*]], ptr [[ALLOCA]], i64 [[SZ2:%.*]], i1 false)
+; CHECK-NEXT: ret void
+;
+ %alloca = alloca <{ [2 x i8], i64, i64, i64 }>
+ %offset = getelementptr i8, ptr %alloca, i64 2
+ call void @llvm.memset.p0.i64(ptr %offset, i8 0, i64 %sz1, i1 false)
+ call void @llvm.memcpy.p0.p0.i64(ptr %out, ptr %alloca, i64 %sz2, i1 false)
+ ret void
+}
+
declare ptr @malloc(i64)
declare void @free(ptr)
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