| ; RUN: opt < %s -analyze -enable-new-pm=0 -scalar-evolution | FileCheck %s |
| ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s |
| |
| ; ScalarEvolution should be able to understand the loop and eliminate the casts. |
| |
| ; CHECK: {%d,+,4} |
| |
| define void @foo(i32* nocapture %d, i32 %n) nounwind { |
| entry: |
| %0 = icmp sgt i32 %n, 0 ; <i1> [#uses=1] |
| br i1 %0, label %bb.nph, label %return |
| |
| bb.nph: ; preds = %entry |
| br label %bb |
| |
| bb: ; preds = %bb1, %bb.nph |
| %i.02 = phi i32 [ %5, %bb1 ], [ 0, %bb.nph ] ; <i32> [#uses=2] |
| %p.01 = phi i8 [ %4, %bb1 ], [ -1, %bb.nph ] ; <i8> [#uses=2] |
| %1 = sext i8 %p.01 to i32 ; <i32> [#uses=1] |
| %2 = sext i32 %i.02 to i64 ; <i64> [#uses=1] |
| %3 = getelementptr i32, i32* %d, i64 %2 ; <i32*> [#uses=1] |
| store i32 %1, i32* %3, align 4 |
| %4 = add i8 %p.01, 1 ; <i8> [#uses=1] |
| %5 = add i32 %i.02, 1 ; <i32> [#uses=2] |
| br label %bb1 |
| |
| bb1: ; preds = %bb |
| %6 = icmp slt i32 %5, %n ; <i1> [#uses=1] |
| br i1 %6, label %bb, label %bb1.return_crit_edge |
| |
| bb1.return_crit_edge: ; preds = %bb1 |
| br label %return |
| |
| return: ; preds = %bb1.return_crit_edge, %entry |
| ret void |
| } |
| |
| ; ScalarEvolution should be able to find the maximum tripcount |
| ; of this multiple-exit loop, and if it doesn't know the exact |
| ; count, it should say so. |
| |
| ; PR7845 |
| ; CHECK: Loop %for.cond: <multiple exits> Unpredictable backedge-taken count. |
| ; CHECK: Loop %for.cond: max backedge-taken count is 5 |
| |
| @.str = private constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=2] |
| |
| define i32 @main() nounwind { |
| entry: |
| br label %for.cond |
| |
| for.cond: ; preds = %for.inc, %entry |
| %g_4.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ] ; <i32> [#uses=5] |
| %cmp = icmp slt i32 %g_4.0, 5 ; <i1> [#uses=1] |
| br i1 %cmp, label %for.body, label %for.end |
| |
| for.body: ; preds = %for.cond |
| %conv = trunc i32 %g_4.0 to i16 ; <i16> [#uses=1] |
| %tobool.not = icmp eq i16 %conv, 0 ; <i1> [#uses=1] |
| %tobool3 = icmp ne i32 %g_4.0, 0 ; <i1> [#uses=1] |
| %or.cond = and i1 %tobool.not, %tobool3 ; <i1> [#uses=1] |
| br i1 %or.cond, label %for.end, label %for.inc |
| |
| for.inc: ; preds = %for.body |
| %add = add nsw i32 %g_4.0, 1 ; <i32> [#uses=1] |
| br label %for.cond |
| |
| for.end: ; preds = %for.body, %for.cond |
| %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0] |
| ret i32 0 |
| } |
| |
| declare i32 @printf(i8*, ...) |
| |
| define void @test(i8* %a, i32 %n) nounwind { |
| entry: |
| %cmp1 = icmp sgt i32 %n, 0 |
| br i1 %cmp1, label %for.body.lr.ph, label %for.end |
| |
| for.body.lr.ph: ; preds = %entry |
| %tmp = zext i32 %n to i64 |
| br label %for.body |
| |
| for.body: ; preds = %for.body, %for.body.lr.ph |
| %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.lr.ph ] |
| %arrayidx = getelementptr i8, i8* %a, i64 %indvar |
| store i8 0, i8* %arrayidx, align 1 |
| %indvar.next = add i64 %indvar, 1 |
| %exitcond = icmp ne i64 %indvar.next, %tmp |
| br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge |
| |
| for.cond.for.end_crit_edge: ; preds = %for.body |
| br label %for.end |
| |
| for.end: ; preds = %for.cond.for.end_crit_edge, %entry |
| ret void |
| } |
| |
| ; CHECK: Determining loop execution counts for: @test |
| ; CHECK-NEXT: backedge-taken count is |
| ; CHECK-NEXT: max backedge-taken count is 4294967294 |
| |
| ; PR19799: Indvars miscompile due to an incorrect max backedge taken count from SCEV. |
| ; CHECK-LABEL: @pr19799 |
| ; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count. |
| ; CHECK: Loop %for.body.i: max backedge-taken count is 1 |
| @a = common global i32 0, align 4 |
| |
| define i32 @pr19799() { |
| entry: |
| store i32 -1, i32* @a, align 4 |
| br label %for.body.i |
| |
| for.body.i: ; preds = %for.cond.i, %entry |
| %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ] |
| %tobool.i = icmp eq i32 %storemerge1.i, 0 |
| %add.i.i = add nsw i32 %storemerge1.i, 2 |
| br i1 %tobool.i, label %bar.exit, label %for.cond.i |
| |
| for.cond.i: ; preds = %for.body.i |
| store i32 %add.i.i, i32* @a, align 4 |
| %cmp.i = icmp slt i32 %storemerge1.i, 0 |
| br i1 %cmp.i, label %for.body.i, label %bar.exit |
| |
| bar.exit: ; preds = %for.cond.i, %for.body.i |
| ret i32 0 |
| } |
| |
| ; PR18886: Indvars miscompile due to an incorrect max backedge taken count from SCEV. |
| ; CHECK-LABEL: @pr18886 |
| ; CHECK: Loop %for.body: <multiple exits> Unpredictable backedge-taken count. |
| ; CHECK: Loop %for.body: max backedge-taken count is 3 |
| @aa = global i64 0, align 8 |
| |
| define i32 @pr18886() { |
| entry: |
| store i64 -21, i64* @aa, align 8 |
| br label %for.body |
| |
| for.body: |
| %storemerge1 = phi i64 [ -21, %entry ], [ %add, %for.cond ] |
| %tobool = icmp eq i64 %storemerge1, 0 |
| %add = add nsw i64 %storemerge1, 8 |
| br i1 %tobool, label %return, label %for.cond |
| |
| for.cond: |
| store i64 %add, i64* @aa, align 8 |
| %cmp = icmp slt i64 %add, 9 |
| br i1 %cmp, label %for.body, label %return |
| |
| return: |
| %retval.0 = phi i32 [ 1, %for.body ], [ 0, %for.cond ] |
| ret i32 %retval.0 |
| } |
| |
| ; Here we have a must-exit loop latch that is not computable and a |
| ; may-exit early exit that can only have one non-exiting iteration |
| ; before the check is forever skipped. |
| ; |
| ; CHECK-LABEL: @cannot_compute_mustexit |
| ; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count. |
| ; CHECK: Loop %for.body.i: Unpredictable max backedge-taken count. |
| @b = common global i32 0, align 4 |
| |
| define i32 @cannot_compute_mustexit() { |
| entry: |
| store i32 -1, i32* @a, align 4 |
| br label %for.body.i |
| |
| for.body.i: ; preds = %for.cond.i, %entry |
| %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ] |
| %tobool.i = icmp eq i32 %storemerge1.i, 0 |
| %add.i.i = add nsw i32 %storemerge1.i, 2 |
| br i1 %tobool.i, label %bar.exit, label %for.cond.i |
| |
| for.cond.i: ; preds = %for.body.i |
| store i32 %add.i.i, i32* @a, align 4 |
| %ld = load volatile i32, i32* @b |
| %cmp.i = icmp ne i32 %ld, 0 |
| br i1 %cmp.i, label %for.body.i, label %bar.exit |
| |
| bar.exit: ; preds = %for.cond.i, %for.body.i |
| ret i32 0 |
| } |
| |
| ; This loop has two must-exits, both of which dominate the latch. The |
| ; MaxBECount should be the minimum of them. |
| ; |
| ; CHECK-LABEL: @two_mustexit |
| ; CHECK: Loop %for.body.i: <multiple exits> backedge-taken count is 1 |
| ; CHECK: Loop %for.body.i: max backedge-taken count is 1 |
| define i32 @two_mustexit() { |
| entry: |
| store i32 -1, i32* @a, align 4 |
| br label %for.body.i |
| |
| for.body.i: ; preds = %for.cond.i, %entry |
| %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ] |
| %tobool.i = icmp sgt i32 %storemerge1.i, 0 |
| %add.i.i = add nsw i32 %storemerge1.i, 2 |
| br i1 %tobool.i, label %bar.exit, label %for.cond.i |
| |
| for.cond.i: ; preds = %for.body.i |
| store i32 %add.i.i, i32* @a, align 4 |
| %cmp.i = icmp slt i32 %storemerge1.i, 3 |
| br i1 %cmp.i, label %for.body.i, label %bar.exit |
| |
| bar.exit: ; preds = %for.cond.i, %for.body.i |
| ret i32 0 |
| } |
| |
| ; CHECK-LABEL: @ne_max_trip_count_1 |
| ; CHECK: Loop %for.body: max backedge-taken count is 7 |
| define i32 @ne_max_trip_count_1(i32 %n) { |
| entry: |
| %masked = and i32 %n, 7 |
| br label %for.body |
| |
| for.body: |
| %i = phi i32 [ 0, %entry ], [ %add, %for.body ] |
| %add = add nsw i32 %i, 1 |
| %cmp = icmp ne i32 %i, %masked |
| br i1 %cmp, label %for.body, label %bar.exit |
| |
| bar.exit: |
| ret i32 0 |
| } |
| |
| ; CHECK-LABEL: @ne_max_trip_count_2 |
| ; CHECK: Loop %for.body: max backedge-taken count is -1 |
| define i32 @ne_max_trip_count_2(i32 %n) { |
| entry: |
| %masked = and i32 %n, 7 |
| br label %for.body |
| |
| for.body: |
| %i = phi i32 [ 0, %entry ], [ %add, %for.body ] |
| %add = add nsw i32 %i, 1 |
| %cmp = icmp ne i32 %add, %masked |
| br i1 %cmp, label %for.body, label %bar.exit |
| |
| bar.exit: |
| ret i32 0 |
| } |
| |
| ; CHECK-LABEL: @ne_max_trip_count_3 |
| ; CHECK: Loop %for.body: max backedge-taken count is 6 |
| define i32 @ne_max_trip_count_3(i32 %n) { |
| entry: |
| %masked = and i32 %n, 7 |
| %guard = icmp eq i32 %masked, 0 |
| br i1 %guard, label %exit, label %for.preheader |
| |
| for.preheader: |
| br label %for.body |
| |
| for.body: |
| %i = phi i32 [ 0, %for.preheader ], [ %add, %for.body ] |
| %add = add nsw i32 %i, 1 |
| %cmp = icmp ne i32 %add, %masked |
| br i1 %cmp, label %for.body, label %loop.exit |
| |
| loop.exit: |
| br label %exit |
| |
| exit: |
| ret i32 0 |
| } |
| |
| ; CHECK-LABEL: @ne_max_trip_count_4 |
| ; CHECK: Loop %for.body: max backedge-taken count is -2 |
| define i32 @ne_max_trip_count_4(i32 %n) { |
| entry: |
| %guard = icmp eq i32 %n, 0 |
| br i1 %guard, label %exit, label %for.preheader |
| |
| for.preheader: |
| br label %for.body |
| |
| for.body: |
| %i = phi i32 [ 0, %for.preheader ], [ %add, %for.body ] |
| %add = add nsw i32 %i, 1 |
| %cmp = icmp ne i32 %add, %n |
| br i1 %cmp, label %for.body, label %loop.exit |
| |
| loop.exit: |
| br label %exit |
| |
| exit: |
| ret i32 0 |
| } |
| |
| ; The end bound of the loop can change between iterations, so the exact trip |
| ; count is unknown, but SCEV can calculate the max trip count. |
| define void @changing_end_bound(i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: max backedge-taken count is 2147483646 |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add nsw i32 %iv, 1 |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |
| |
| ; Similar test as above, but unknown start value. |
| ; Also, there's no nsw on the iv.next, but SCEV knows |
| ; the termination condition is LT, so the IV cannot wrap. |
| define void @changing_end_bound2(i32 %start, i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound2 |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: max backedge-taken count is -1 |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add i32 %iv, 1 |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |
| |
| ; changing end bound and greater than one stride |
| define void @changing_end_bound3(i32 %start, i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound3 |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: max backedge-taken count is 1073741823 |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add nsw i32 %iv, 4 |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |
| |
| ; same as above test, but the IV can wrap around. |
| ; so the max backedge taken count is unpredictable. |
| define void @changing_end_bound4(i32 %start, i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound4 |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: Unpredictable max backedge-taken count. |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add i32 %iv, 4 |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |
| |
| ; unknown stride. Since it's not knownPositive, we do not estimate the max |
| ; backedge taken count. |
| define void @changing_end_bound5(i32 %stride, i32 %start, i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound5 |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: Unpredictable max backedge-taken count. |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add nsw i32 %iv, %stride |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |
| |
| ; negative stride value |
| define void @changing_end_bound6(i32 %start, i32* %n_addr, i32* %addr) { |
| ; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound6 |
| ; CHECK: Loop %loop: Unpredictable backedge-taken count. |
| ; CHECK: Loop %loop: Unpredictable max backedge-taken count. |
| entry: |
| br label %loop |
| |
| loop: |
| %iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ] |
| %acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ] |
| %val = load atomic i32, i32* %addr unordered, align 4 |
| fence acquire |
| %acc.next = add i32 %acc, %val |
| %iv.next = add nsw i32 %iv, -1 |
| %n = load atomic i32, i32* %n_addr unordered, align 4 |
| %cmp = icmp slt i32 %iv.next, %n |
| br i1 %cmp, label %loop, label %loop.exit |
| |
| loop.exit: |
| ret void |
| } |