1; RUN: opt -S -passes=instcombine,simplify-cfg < %s 2>&1 | FileCheck %s 2 3declare void @llvm.assume(i1 noundef) 4 5define void @f1(i8* %a) { 6; CHECK-LABEL: @f1( 7; CHECK-NEXT: entry: 8; CHECK-NEXT: [[PTR:%.*]] = getelementptr inbounds i8, i8* [[A:%.*]], i64 4 9; CHECK-NEXT: [[TMP0:%.*]] = ptrtoint i8* [[PTR]] to i64 10; CHECK-NEXT: [[TMP1:%.*]] = and i64 [[TMP0]], 3 11; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 0 12; CHECK-NEXT: br i1 [[TMP2]], label [[IF_THEN:%.*]], label [[IF_END:%.*]] 13; CHECK: if.then: 14; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(i8* [[PTR]], i64 4) ] 15; CHECK-NEXT: [[TMP3:%.*]] = bitcast i8* [[PTR]] to i32* 16; CHECK-NEXT: store i32 4, i32* [[TMP3]], align 4 17; CHECK-NEXT: br label [[IF_END]] 18; CHECK: if.end: 19; CHECK-NEXT: ret void 20; 21entry: 22 %ptr = getelementptr inbounds i8, i8* %a, i64 4 23 %0 = ptrtoint i8* %ptr to i64 24 %1 = and i64 %0, 3 25 %2 = icmp eq i64 %1, 0 26 br i1 %2, label %if.then, label %if.end 27 28if.then: ; preds = %entry 29 call void @llvm.assume(i1 true) [ "align"(i8* %ptr, i64 4) ] 30 %3 = ptrtoint i8* %ptr to i64 31 %4 = and i64 %3, 3 32 %5 = icmp eq i64 %4, 0 33 br i1 %5, label %if.then1, label %if.else1 34 35if.then1: ; preds = %if.then 36 %6 = bitcast i8* %ptr to i32* 37 store i32 4, i32* %6, align 4 38 br label %if.end 39 40if.else1: ; preds = %if.then 41 store i8 1, i8* %ptr, align 1 42 br label %if.end 43 44if.end: ; preds = %if.then1, %if.else1, %entry 45 ret void 46} 47 48; TODO: We could fold away the branch "br i1 %3, ..." by either using a GEP or make getKnowledgeValidInContext aware the alignment bundle offset, and the improvement of value tracking of GEP. 49 50define void @f2(i8* %a) { 51; CHECK-LABEL: @f2( 52; CHECK-NEXT: entry: 53; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(i8* [[A:%.*]], i64 32, i32 24) ] 54; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds i8, i8* [[A]], i64 8 55; CHECK-NEXT: [[TMP1:%.*]] = ptrtoint i8* [[TMP0]] to i64 56; CHECK-NEXT: [[TMP2:%.*]] = and i64 [[TMP1]], 8 57; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i64 [[TMP2]], 0 58; CHECK-NEXT: br i1 [[TMP3]], label [[IF_THEN1:%.*]], label [[IF_ELSE1:%.*]] 59; 60entry: 61 call void @llvm.assume(i1 true) [ "align"(i8* %a, i64 32, i32 24) ] 62 %0 = getelementptr inbounds i8, i8* %a, i64 8 63 %1 = ptrtoint i8* %0 to i64 64 %2 = and i64 %1, 15 65 %3 = icmp eq i64 %2, 0 66 br i1 %3, label %if.then, label %if.else 67 68if.then: ; preds = %entry 69 %4 = bitcast i8* %0 to i64* 70 store i64 16, i64* %4, align 4 71 br label %if.end 72 73if.else: ; preds = %entry 74 store i8 1, i8* %0, align 1 75 br label %if.end 76 77if.end: ; preds = %if.else, %if.then 78 ret void 79} 80 81