; RUN: opt -passes=print-access-info %s -disable-output 2>&1 | FileCheck %s target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128" ; i and i + 1 can overflow in the following kernel: ; void test1(unsigned long long x, int *a, int *b) { ; for (unsigned i = 0; i < x; ++i) ; b[i] = a[i+1] + 1; ; } ; ; If accesses to a and b can alias, we need to emit a run-time alias check ; between accesses to a and b. However, when i and i + 1 can wrap, their ; SCEV expression is not an AddRec. We need to create SCEV predicates and ; coerce the expressions to AddRecs in order to be able to emit the run-time ; alias check. ; ; The accesses at b[i] and a[i+1] correspond to the addresses %arrayidx and ; %arrayidx4 in the test. The SCEV expressions for these are: ; ((4 * (zext i32 {1,+,1}<%for.body> to i64))<nuw><nsw> + %a)<nsw> ; ((4 * (zext i32 {0,+,1}<%for.body> to i64))<nuw><nsw> + %b)<nsw> ; ; The transformed expressions are: ; i64 {(4 + %a),+,4}<%for.body> ; i64 {(4 + %b),+,4}<%for.body> ; CHECK-LABEL: test1 ; CHECK: Memory dependences are safe with run-time checks ; CHECK-NEXT: Dependences: ; CHECK-NEXT: Run-time memory checks: ; CHECK-NEXT: Check 0: ; CHECK-NEXT: Comparing group ; CHECK-NEXT: %arrayidx = getelementptr inbounds i32, i32* %a, i64 %idxprom ; CHECK-NEXT: Against group ; CHECK-NEXT: %arrayidx4 = getelementptr inbounds i32, i32* %b, i64 %conv11 ; CHECK-NEXT: Grouped accesses: ; CHECK-NEXT: Group ; CHECK-NEXT: (Low: (4 + %a) High: (4 + (4 * (1 umax %x)) + %a)) ; CHECK-NEXT: Member: {(4 + %a),+,4}<%for.body> ; CHECK-NEXT: Group ; CHECK-NEXT: (Low: %b High: ((4 * (1 umax %x)) + %b)) ; CHECK-NEXT: Member: {%b,+,4}<%for.body> ; CHECK: Non vectorizable stores to invariant address were not found in loop. ; CHECK-NEXT: SCEV assumptions: ; CHECK-NEXT: {1,+,1}<%for.body> Added Flags: <nusw> ; CHECK-NEXT: {0,+,1}<%for.body> Added Flags: <nusw> ; CHECK: Expressions re-written: ; CHECK-NEXT: [PSE] %arrayidx = getelementptr inbounds i32, i32* %a, i64 %idxprom: ; CHECK-NEXT: ((4 * (zext i32 {1,+,1}<%for.body> to i64))<nuw><nsw> + %a)<nuw> ; CHECK-NEXT: --> {(4 + %a),+,4}<%for.body> ; CHECK-NEXT: [PSE] %arrayidx4 = getelementptr inbounds i32, i32* %b, i64 %conv11: ; CHECK-NEXT: ((4 * (zext i32 {0,+,1}<%for.body> to i64))<nuw><nsw> + %b)<nuw> ; CHECK-NEXT: --> {%b,+,4}<%for.body> define void @test1(i64 %x, i32* %a, i32* %b) { entry: br label %for.body for.body: ; preds = %for.body.preheader, %for.body %conv11 = phi i64 [ %conv, %for.body ], [ 0, %entry ] %i.010 = phi i32 [ %add, %for.body ], [ 0, %entry ] %add = add i32 %i.010, 1 %idxprom = zext i32 %add to i64 %arrayidx = getelementptr inbounds i32, i32* %a, i64 %idxprom %ld = load i32, i32* %arrayidx, align 4 %add2 = add nsw i32 %ld, 1 %arrayidx4 = getelementptr inbounds i32, i32* %b, i64 %conv11 store i32 %add2, i32* %arrayidx4, align 4 %conv = zext i32 %add to i64 %cmp = icmp ult i64 %conv, %x br i1 %cmp, label %for.body, label %exit exit: ret void } ; i can overflow in the following kernel: ; void test2(unsigned long long x, int *a) { ; for (unsigned i = 0; i < x; ++i) ; a[i] = a[i] + 1; ; } ; ; We need to check that i doesn't wrap, but we don't need a run-time alias ; check. We also need an extra no-wrap check to get the backedge taken count. ; CHECK-LABEL: test2 ; CHECK: Memory dependences are safe ; CHECK: SCEV assumptions: ; CHECK-NEXT: {1,+,1}<%for.body> Added Flags: <nusw> ; CHECK-NEXT: {0,+,1}<%for.body> Added Flags: <nusw> define void @test2(i64 %x, i32* %a) { entry: br label %for.body for.body: %conv11 = phi i64 [ %conv, %for.body ], [ 0, %entry ] %i.010 = phi i32 [ %inc, %for.body ], [ 0, %entry ] %arrayidx = getelementptr inbounds i32, i32* %a, i64 %conv11 %ld = load i32, i32* %arrayidx, align 4 %add = add nsw i32 %ld, 1 store i32 %add, i32* %arrayidx, align 4 %inc = add i32 %i.010, 1 %conv = zext i32 %inc to i64 %cmp = icmp ult i64 %conv, %x br i1 %cmp, label %for.body, label %exit exit: ret void }