; 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 <stdint.h> ; #include <stdio.h> ; ; 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 [[FOR_BODY:%.*]] ; CHECK: for.body: ; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[COND_END:%.*]] ] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[Y:%.*]], 0 ; CHECK-NEXT: br i1 [[CMP]], label [[COND_END]], label [[COND_FALSE:%.*]] ; CHECK: cond.false: ; CHECK-NEXT: [[DIV:%.*]] = xor i64 3, [[Y]] ; CHECK-NEXT: br label [[COND_END]] ; CHECK: cond.end: ; CHECK-NEXT: [[COND:%.*]] = phi i64 [ [[DIV]], [[COND_FALSE]] ], [ 77, [[FOR_BODY]] ] ; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INC]], 3 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], [[COND_END]] ] ; CHECK-NEXT: ret i64 [[COND_LCSSA]] ; 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 [[FOR_BODY:%.*]] ; CHECK: for.body: ; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[COND_END:%.*]] ] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[Y:%.*]], 0 ; CHECK-NEXT: br i1 [[CMP]], label [[COND_END]], label [[COND_FALSE:%.*]] ; CHECK: cond.false: ; CHECK-NEXT: br label [[COND_END]] ; CHECK: cond.end: ; CHECK-NEXT: [[COND:%.*]] = phi i64 [ 55, [[COND_FALSE]] ], [ 77, [[FOR_BODY]] ] ; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INC]], 3 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], [[COND_END]] ] ; CHECK-NEXT: ret i64 [[COND_LCSSA]] ; 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 [[FOR_BODY:%.*]] ; CHECK: for.body: ; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[COND_END:%.*]] ] ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[Y:%.*]], 0 ; CHECK-NEXT: br i1 [[CMP]], label [[COND_END]], label [[COND_FALSE:%.*]] ; CHECK: cond.false: ; CHECK-NEXT: br label [[COND_END]] ; CHECK: cond.end: ; CHECK-NEXT: [[COND:%.*]] = phi i32 [ 55, [[COND_FALSE]] ], [ [[I]], [[FOR_BODY]] ] ; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INC]], 3 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]] ; CHECK: for.cond.cleanup: ; CHECK-NEXT: [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], [[COND_END]] ] ; CHECK-NEXT: ret i32 [[COND_LCSSA]] ; 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 }