; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -passes=loop-vectorize -force-vector-width=4 -S | FileCheck %s ; Test cases below are reduced (and slightly modified) reproducers based on a ; problem seen when compiling a C program like this: ; ; #include ; #include ; ; int y = 0; ; int b = 1; ; int d = 1; ; ; int main() { ; #pragma clang loop vectorize_width(4) ; for (int i = 0; i < 3; ++i) { ; b = (y == 0) ? d : (d / y); ; } ; ; if (b == 1) ; printf("GOOD!\n"); ; else ; printf("BAD!\n"); ; } ; ; When compiled+executed using ; build-all/bin/clang -O1 lv-bug.c && ./a.out ; the result is "GOOD!" ; ; When compiled+executed using ; build-all/bin/clang -O1 lv-bug.c -fvectorize && ./a.out ; the result is "BAD!" ; This test case miscompiled with clang 8.0.0 (see PR43166), now we get ; loop not vectorized: Cannot fold tail by masking in the presence of live outs. ; instead. define i64 @test1(i64 %y) { ; CHECK-LABEL: @test1( ; CHECK-NEXT: entry: ; CHECK-NEXT: br label [[VECTOR_PH:%.*]] ; CHECK: vector.ph: ; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[Y:%.*]], i64 0 ; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer ; CHECK-NEXT: [[TMP0:%.*]] = icmp eq <4 x i64> [[BROADCAST_SPLAT]], zeroinitializer ; CHECK-NEXT: [[TMP1:%.*]] = xor <4 x i64> splat (i64 3), [[BROADCAST_SPLAT]] ; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i1> [[TMP0]], i64 0 ; CHECK-NEXT: [[TMP3:%.*]] = extractelement <4 x i64> [[TMP1]], i64 0 ; CHECK-NEXT: [[TMP5:%.*]] = select i1 [[TMP2]], i64 77, i64 [[TMP3]] ; CHECK-NEXT: br label [[FOR_BODY:%.*]] ; CHECK: vector.body: ; CHECK-NEXT: br label [[MIDDLE_BLOCK:%.*]] ; CHECK: middle.block: ; CHECK-NEXT: br label [[COND_END:%.*]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: ret i64 [[TMP5]] ; entry: br label %for.body for.body: %i = phi i32 [ 0, %entry ], [ %inc, %cond.end ] %cmp = icmp eq i64 %y, 0 br i1 %cmp, label %cond.end, label %cond.false cond.false: %div = xor i64 3, %y br label %cond.end cond.end: %cond = phi i64 [ %div, %cond.false ], [ 77, %for.body ] %inc = add nuw nsw i32 %i, 1 %exitcond = icmp eq i32 %inc, 3 br i1 %exitcond, label %for.cond.cleanup, label %for.body for.cond.cleanup: ret i64 %cond } ; This test case miscompiled with clang 8.0.0 (see PR43166), now we get ; loop not vectorized: Cannot fold tail by masking in the presence of live outs. ; instead. define i64 @test2(i64 %y) { ; CHECK-LABEL: @test2( ; CHECK-NEXT: entry: ; CHECK-NEXT: br label [[VECTOR_PH:%.*]] ; CHECK: vector.ph: ; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[Y:%.*]], 0 ; CHECK-NEXT: [[TMP4:%.*]] = select i1 [[TMP1]], i64 77, i64 55 ; CHECK-NEXT: br label [[FOR_BODY:%.*]] ; CHECK: vector.body: ; CHECK-NEXT: br label [[MIDDLE_BLOCK:%.*]] ; CHECK: middle.block: ; CHECK-NEXT: br label [[COND_END:%.*]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: ret i64 [[TMP4]] ; entry: br label %for.body for.body: %i = phi i32 [ 0, %entry ], [ %inc, %cond.end ] %cmp = icmp eq i64 %y, 0 br i1 %cmp, label %cond.end, label %cond.false cond.false: br label %cond.end cond.end: %cond = phi i64 [ 55, %cond.false ], [ 77, %for.body ] %inc = add nuw nsw i32 %i, 1 %exitcond = icmp eq i32 %inc, 3 br i1 %exitcond, label %for.cond.cleanup, label %for.body for.cond.cleanup: ret i64 %cond } ; This test case miscompiled with clang 8.0.0 (see PR43166), now we get ; loop not vectorized: Cannot fold tail by masking in the presence of live outs. ; instead. define i32 @test3(i64 %y) { ; CHECK-LABEL: @test3( ; CHECK-NEXT: entry: ; CHECK-NEXT: br label [[VECTOR_PH:%.*]] ; CHECK: vector.ph: ; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[Y:%.*]], 0 ; CHECK-NEXT: br label [[FOR_BODY:%.*]] ; CHECK: vector.body: ; CHECK-NEXT: br label [[MIDDLE_BLOCK:%.*]] ; CHECK: middle.block: ; CHECK-NEXT: [[PREDPHI:%.*]] = select i1 [[TMP1]], <4 x i32> , <4 x i32> splat (i32 55) ; CHECK-NEXT: [[TMP2:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> , i1 false) ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], 1 ; CHECK-NEXT: [[TMP4:%.*]] = extractelement <4 x i32> [[PREDPHI]], i64 [[TMP3]] ; CHECK-NEXT: br label [[COND_END:%.*]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: ret i32 [[TMP4]] ; entry: br label %for.body for.body: %i = phi i32 [ 0, %entry ], [ %inc, %cond.end ] %cmp = icmp eq i64 %y, 0 br i1 %cmp, label %cond.end, label %cond.false cond.false: br label %cond.end cond.end: %cond = phi i32 [ 55, %cond.false ], [ %i, %for.body ] %inc = add nuw nsw i32 %i, 1 %exitcond = icmp eq i32 %inc, 3 br i1 %exitcond, label %for.cond.cleanup, label %for.body for.cond.cleanup: ret i32 %cond }