1; REQUIRES: asserts 2; RUN: llc -march=x86-64 -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck -check-prefix=X86 %s 3; RUN: llc -march=x86-64 -mtriple=x86_64-unknown-linux-gnu -debug-only=isel < %s 2>&1 | FileCheck -check-prefix=DBGDAG %s 4 5; It's OK to merge the load / store of the first 2 components, but 6; they must not be placed on the same chain after merging. 7 8; X86-LABEL: {{^}}merge_store_partial_overlap_load: 9; X86-DAG: movw ([[BASEREG:%[a-z]+]]), [[LO2:%[a-z]+]] 10; X86-DAG: movb 2([[BASEREG]]), [[HI1:%[a-z]+]] 11 12; X86-NEXT: movw [[LO2]], 1([[BASEREG]]) 13; X86-NEXT: movb [[HI1]], 3([[BASEREG]]) 14; X86-NEXT: retq 15 16; DBGDAG-LABEL: Optimized lowered selection DAG: BB#0 'merge_store_partial_overlap_load:' 17; DBGDAG: [[ENTRYTOKEN:t[0-9]+]]: ch = EntryToken 18; DBGDAG-DAG: [[BASEPTR:t[0-9]+]]: i64,ch = CopyFromReg [[ENTRYTOKEN]], 19; DBGDAG-DAG: [[ADDPTR:t[0-9]+]]: i64 = add [[BASEPTR]], Constant:i64<2> 20 21; DBGDAG-DAG: [[LD2:t[0-9]+]]: i16,ch = load<LD2[%tmp81](align=1)> [[ENTRYTOKEN]], [[BASEPTR]], undef:i64 22; DBGDAG-DAG: [[LD1:t[0-9]+]]: i8,ch = load<LD1[%tmp12]> [[ENTRYTOKEN]], [[ADDPTR]], undef:i64 23 24; DBGDAG: [[LOADTOKEN:t[0-9]+]]: ch = TokenFactor [[LD2]]:1, [[LD1]]:1 25 26; DBGDAG-DAG: [[ST2:t[0-9]+]]: ch = store<ST2[%tmp10](align=1)> [[LOADTOKEN]], [[LD2]], t{{[0-9]+}}, undef:i64 27; DBGDAG-DAG: [[ST1:t[0-9]+]]: ch = store<ST1[%tmp14]> [[ST2]], [[LD1]], t{{[0-9]+}}, undef:i64 28; DBGDAG: X86ISD::RET_FLAG [[ST1]], 29 30; DBGDAG: Type-legalized selection DAG: BB#0 'merge_store_partial_overlap_load:' 31define void @merge_store_partial_overlap_load([4 x i8]* %tmp) { 32 %tmp8 = getelementptr inbounds [4 x i8], [4 x i8]* %tmp, i32 0, i8 0 33 %tmp10 = getelementptr inbounds [4 x i8], [4 x i8]* %tmp, i32 0, i8 1 34 %tmp12 = getelementptr inbounds [4 x i8], [4 x i8]* %tmp, i32 0, i8 2 35 %tmp14 = getelementptr [4 x i8], [4 x i8]* %tmp, i32 0, i8 3 36 37 %tmp9 = load i8, i8* %tmp8, align 1 ; base + 0 38 %tmp11 = load i8, i8* %tmp10, align 1 ; base + 1 39 %tmp13 = load i8, i8* %tmp12, align 1 ; base + 2 40 41 store i8 %tmp9, i8* %tmp10, align 1 ; base + 1 42 store i8 %tmp11, i8* %tmp12, align 1 ; base + 2 43 store i8 %tmp13, i8* %tmp14, align 1 ; base + 3 44 45; Should emit 46; load base + 0, base + 1 47; store base + 1, base + 2 48; load base + 2 49; store base + 3 50 51 ret void 52} 53