; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -indvars -S | FileCheck %s ; Provide legal integer types. target datalayout = "n8:16:32:64" ; CHECK-NOT: sext define i64 @test(i64* nocapture %first, i32 %count) nounwind readonly { ; CHECK-LABEL: @test( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[T0:%.*]] = icmp sgt i32 [[COUNT:%.*]], 0 ; CHECK-NEXT: br i1 [[T0]], label [[BB_NPH:%.*]], label [[BB2:%.*]] ; CHECK: bb.nph: ; CHECK-NEXT: [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[COUNT]] to i64 ; CHECK-NEXT: br label [[BB:%.*]] ; CHECK: bb: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[BB1:%.*]] ], [ 0, [[BB_NPH]] ] ; CHECK-NEXT: [[RESULT_02:%.*]] = phi i64 [ [[T5:%.*]], [[BB1]] ], [ 0, [[BB_NPH]] ] ; CHECK-NEXT: [[T2:%.*]] = getelementptr i64, i64* [[FIRST:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: [[T3:%.*]] = load i64, i64* [[T2]], align 8 ; CHECK-NEXT: [[T4:%.*]] = lshr i64 [[T3]], 4 ; CHECK-NEXT: [[T5]] = add i64 [[T4]], [[RESULT_02]] ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br label [[BB1]] ; CHECK: bb1: ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT]], [[WIDE_TRIP_COUNT]] ; CHECK-NEXT: br i1 [[EXITCOND]], label [[BB]], label [[BB1_BB2_CRIT_EDGE:%.*]] ; CHECK: bb1.bb2_crit_edge: ; CHECK-NEXT: [[DOTLCSSA:%.*]] = phi i64 [ [[T5]], [[BB1]] ] ; CHECK-NEXT: br label [[BB2]] ; CHECK: bb2: ; CHECK-NEXT: [[RESULT_0_LCSSA:%.*]] = phi i64 [ [[DOTLCSSA]], [[BB1_BB2_CRIT_EDGE]] ], [ 0, [[ENTRY:%.*]] ] ; CHECK-NEXT: ret i64 [[RESULT_0_LCSSA]] ; entry: %t0 = icmp sgt i32 %count, 0 ; <i1> [#uses=1] br i1 %t0, label %bb.nph, label %bb2 bb.nph: ; preds = %entry br label %bb bb: ; preds = %bb1, %bb.nph %result.02 = phi i64 [ %t5, %bb1 ], [ 0, %bb.nph ] ; <i64> [#uses=1] %n.01 = phi i32 [ %t6, %bb1 ], [ 0, %bb.nph ] ; <i32> [#uses=2] %t1 = sext i32 %n.01 to i64 ; <i64> [#uses=1] %t2 = getelementptr i64, i64* %first, i64 %t1 ; <i64*> [#uses=1] %t3 = load i64, i64* %t2, align 8 ; <i64> [#uses=1] %t4 = lshr i64 %t3, 4 ; <i64> [#uses=1] %t5 = add i64 %t4, %result.02 ; <i64> [#uses=2] %t6 = add i32 %n.01, 1 ; <i32> [#uses=2] br label %bb1 bb1: ; preds = %bb %t7 = icmp slt i32 %t6, %count ; <i1> [#uses=1] br i1 %t7, label %bb, label %bb1.bb2_crit_edge bb1.bb2_crit_edge: ; preds = %bb1 %.lcssa = phi i64 [ %t5, %bb1 ] ; <i64> [#uses=1] br label %bb2 bb2: ; preds = %bb1.bb2_crit_edge, %entry %result.0.lcssa = phi i64 [ %.lcssa, %bb1.bb2_crit_edge ], [ 0, %entry ] ; <i64> [#uses=1] ret i64 %result.0.lcssa } define void @foo(i16 signext %N, i32* nocapture %P) nounwind { ; CHECK-LABEL: @foo( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[T0:%.*]] = icmp sgt i16 [[N:%.*]], 0 ; CHECK-NEXT: br i1 [[T0]], label [[BB_NPH:%.*]], label [[RETURN:%.*]] ; CHECK: bb.nph: ; CHECK-NEXT: [[WIDE_TRIP_COUNT:%.*]] = zext i16 [[N]] to i64 ; CHECK-NEXT: br label [[BB:%.*]] ; CHECK: bb: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[BB1:%.*]] ], [ 0, [[BB_NPH]] ] ; CHECK-NEXT: [[T2:%.*]] = getelementptr i32, i32* [[P:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store i32 123, i32* [[T2]], align 4 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br label [[BB1]] ; CHECK: bb1: ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT]], [[WIDE_TRIP_COUNT]] ; CHECK-NEXT: br i1 [[EXITCOND]], label [[BB]], label [[BB1_RETURN_CRIT_EDGE:%.*]] ; CHECK: bb1.return_crit_edge: ; CHECK-NEXT: br label [[RETURN]] ; CHECK: return: ; CHECK-NEXT: ret void ; entry: %t0 = icmp sgt i16 %N, 0 ; <i1> [#uses=1] br i1 %t0, label %bb.nph, label %return bb.nph: ; preds = %entry br label %bb bb: ; preds = %bb1, %bb.nph %i.01 = phi i16 [ %t3, %bb1 ], [ 0, %bb.nph ] ; <i16> [#uses=2] %t1 = sext i16 %i.01 to i64 ; <i64> [#uses=1] %t2 = getelementptr i32, i32* %P, i64 %t1 ; <i32*> [#uses=1] store i32 123, i32* %t2, align 4 %t3 = add i16 %i.01, 1 ; <i16> [#uses=2] br label %bb1 bb1: ; preds = %bb %t4 = icmp slt i16 %t3, %N ; <i1> [#uses=1] br i1 %t4, 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 } ; Test cases from PR1301: define void @kinds__srangezero([21 x i32]* nocapture %a) nounwind { ; CHECK-LABEL: @kinds__srangezero( ; CHECK-NEXT: bb.thread: ; CHECK-NEXT: br label [[BB:%.*]] ; CHECK: bb: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i32 [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ], [ -10, [[BB_THREAD:%.*]] ] ; CHECK-NEXT: [[TMP4:%.*]] = add nsw i32 [[INDVARS_IV]], 10 ; CHECK-NEXT: [[TMP5:%.*]] = getelementptr [21 x i32], [21 x i32]* [[A:%.*]], i32 0, i32 [[TMP4]] ; CHECK-NEXT: store i32 0, i32* [[TMP5]], align 4 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i32 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INDVARS_IV_NEXT]], 11 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[RETURN:%.*]], label [[BB]] ; CHECK: return: ; CHECK-NEXT: ret void ; bb.thread: br label %bb bb: ; preds = %bb, %bb.thread %i.0.reg2mem.0 = phi i8 [ -10, %bb.thread ], [ %tmp7, %bb ] ; <i8> [#uses=2] %tmp12 = sext i8 %i.0.reg2mem.0 to i32 ; <i32> [#uses=1] %tmp4 = add i32 %tmp12, 10 ; <i32> [#uses=1] %tmp5 = getelementptr [21 x i32], [21 x i32]* %a, i32 0, i32 %tmp4 ; <i32*> [#uses=1] store i32 0, i32* %tmp5 %tmp7 = add i8 %i.0.reg2mem.0, 1 ; <i8> [#uses=2] %0 = icmp sgt i8 %tmp7, 10 ; <i1> [#uses=1] br i1 %0, label %return, label %bb return: ; preds = %bb ret void } define void @kinds__urangezero([21 x i32]* nocapture %a) nounwind { ; CHECK-LABEL: @kinds__urangezero( ; CHECK-NEXT: bb.thread: ; CHECK-NEXT: br label [[BB:%.*]] ; CHECK: bb: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i32 [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ], [ 10, [[BB_THREAD:%.*]] ] ; CHECK-NEXT: [[TMP4:%.*]] = add nsw i32 [[INDVARS_IV]], -10 ; CHECK-NEXT: [[TMP5:%.*]] = getelementptr [21 x i32], [21 x i32]* [[A:%.*]], i32 0, i32 [[TMP4]] ; CHECK-NEXT: store i32 0, i32* [[TMP5]], align 4 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i32 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INDVARS_IV_NEXT]], 31 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[RETURN:%.*]], label [[BB]] ; CHECK: return: ; CHECK-NEXT: ret void ; bb.thread: br label %bb bb: ; preds = %bb, %bb.thread %i.0.reg2mem.0 = phi i8 [ 10, %bb.thread ], [ %tmp7, %bb ] ; <i8> [#uses=2] %tmp12 = sext i8 %i.0.reg2mem.0 to i32 ; <i32> [#uses=1] %tmp4 = add i32 %tmp12, -10 ; <i32> [#uses=1] %tmp5 = getelementptr [21 x i32], [21 x i32]* %a, i32 0, i32 %tmp4 ; <i32*> [#uses=1] store i32 0, i32* %tmp5 %tmp7 = add i8 %i.0.reg2mem.0, 1 ; <i8> [#uses=2] %0 = icmp sgt i8 %tmp7, 30 ; <i1> [#uses=1] br i1 %0, label %return, label %bb return: ; preds = %bb ret void } define void @promote_latch_condition_decrementing_loop_01(i32* %p, i32* %a) { ; CHECK-LABEL: @promote_latch_condition_decrementing_loop_01( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[P:%.*]], align 4, !range [[RNG0:![0-9]+]] ; CHECK-NEXT: [[LEN_MINUS_1:%.*]] = add i32 [[LEN]], -1 ; CHECK-NEXT: [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0 ; CHECK-NEXT: br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]] ; CHECK: preheader: ; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[LEN_MINUS_1]] to i64 ; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK: loopexit.loopexit: ; CHECK-NEXT: br label [[LOOPEXIT]] ; CHECK: loopexit: ; CHECK-NEXT: ret void ; CHECK: loop: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ] ; CHECK-NEXT: [[EL:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store atomic i32 0, i32* [[EL]] unordered, align 4 ; CHECK-NEXT: [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1 ; CHECK-NEXT: br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]] ; entry: %len = load i32, i32* %p, align 4, !range !0 %len.minus.1 = add nsw i32 %len, -1 %zero_check = icmp eq i32 %len, 0 br i1 %zero_check, label %loopexit, label %preheader preheader: br label %loop loopexit: ret void loop: %iv = phi i32 [ %iv.next, %loop ], [ %len.minus.1, %preheader ] %iv.wide = zext i32 %iv to i64 %el = getelementptr inbounds i32, i32* %a, i64 %iv.wide store atomic i32 0, i32* %el unordered, align 4 %iv.next = add nsw i32 %iv, -1 %loopcond = icmp slt i32 %iv, 1 br i1 %loopcond, label %loopexit, label %loop } define void @promote_latch_condition_decrementing_loop_02(i32* %p, i32* %a) { ; CHECK-LABEL: @promote_latch_condition_decrementing_loop_02( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[P:%.*]], align 4, !range [[RNG0]] ; CHECK-NEXT: [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0 ; CHECK-NEXT: br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]] ; CHECK: preheader: ; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[LEN]] to i64 ; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK: loopexit.loopexit: ; CHECK-NEXT: br label [[LOOPEXIT]] ; CHECK: loopexit: ; CHECK-NEXT: ret void ; CHECK: loop: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ] ; CHECK-NEXT: [[EL:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store atomic i32 0, i32* [[EL]] unordered, align 4 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1 ; CHECK-NEXT: [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]] ; entry: %len = load i32, i32* %p, align 4, !range !0 %zero_check = icmp eq i32 %len, 0 br i1 %zero_check, label %loopexit, label %preheader preheader: br label %loop loopexit: ret void loop: %iv = phi i32 [ %iv.next, %loop ], [ %len, %preheader ] %iv.wide = zext i32 %iv to i64 %el = getelementptr inbounds i32, i32* %a, i64 %iv.wide store atomic i32 0, i32* %el unordered, align 4 %iv.next = add nsw i32 %iv, -1 %loopcond = icmp slt i32 %iv, 1 br i1 %loopcond, label %loopexit, label %loop } define void @promote_latch_condition_decrementing_loop_03(i32* %p, i32* %a) { ; CHECK-LABEL: @promote_latch_condition_decrementing_loop_03( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[P:%.*]], align 4, !range [[RNG0]] ; CHECK-NEXT: [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0 ; CHECK-NEXT: br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]] ; CHECK: preheader: ; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[LEN]] to i64 ; CHECK-NEXT: [[TMP1:%.*]] = add nuw nsw i64 [[TMP0]], 1 ; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK: loopexit.loopexit: ; CHECK-NEXT: br label [[LOOPEXIT]] ; CHECK: loopexit: ; CHECK-NEXT: ret void ; CHECK: loop: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP1]], [[PREHEADER]] ] ; CHECK-NEXT: [[EL:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store atomic i32 0, i32* [[EL]] unordered, align 4 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1 ; CHECK-NEXT: [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]] ; entry: %len = load i32, i32* %p, align 4, !range !0 %len.plus.1 = add i32 %len, 1 %zero_check = icmp eq i32 %len, 0 br i1 %zero_check, label %loopexit, label %preheader preheader: br label %loop loopexit: ret void loop: %iv = phi i32 [ %iv.next, %loop ], [ %len.plus.1, %preheader ] %iv.wide = zext i32 %iv to i64 %el = getelementptr inbounds i32, i32* %a, i64 %iv.wide store atomic i32 0, i32* %el unordered, align 4 %iv.next = add nsw i32 %iv, -1 %loopcond = icmp slt i32 %iv, 1 br i1 %loopcond, label %loopexit, label %loop } define void @promote_latch_condition_decrementing_loop_04(i32* %p, i32* %a, i1 %cond) { ; CHECK-LABEL: @promote_latch_condition_decrementing_loop_04( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[P:%.*]], align 4, !range [[RNG0]] ; CHECK-NEXT: [[LEN_MINUS_1:%.*]] = add nsw i32 [[LEN]], -1 ; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]] ; CHECK: if.true: ; CHECK-NEXT: br label [[MERGE:%.*]] ; CHECK: if.false: ; CHECK-NEXT: br label [[MERGE]] ; CHECK: merge: ; CHECK-NEXT: [[IV_START:%.*]] = phi i32 [ [[LEN]], [[IF_TRUE]] ], [ [[LEN_MINUS_1]], [[IF_FALSE]] ] ; CHECK-NEXT: [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0 ; CHECK-NEXT: br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]] ; CHECK: preheader: ; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[IV_START]] to i64 ; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK: loopexit.loopexit: ; CHECK-NEXT: br label [[LOOPEXIT]] ; CHECK: loopexit: ; CHECK-NEXT: ret void ; CHECK: loop: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ] ; CHECK-NEXT: [[EL:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store atomic i32 0, i32* [[EL]] unordered, align 4 ; CHECK-NEXT: [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1 ; CHECK-NEXT: br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]] ; entry: %len = load i32, i32* %p, align 4, !range !0 %len.minus.1 = add nsw i32 %len, -1 br i1 %cond, label %if.true, label %if.false if.true: br label %merge if.false: br label %merge merge: %iv_start = phi i32 [ %len, %if.true ], [%len.minus.1, %if.false ] %zero_check = icmp eq i32 %len, 0 br i1 %zero_check, label %loopexit, label %preheader preheader: br label %loop loopexit: ret void loop: %iv = phi i32 [ %iv.next, %loop ], [ %iv_start, %preheader ] %iv.wide = zext i32 %iv to i64 %el = getelementptr inbounds i32, i32* %a, i64 %iv.wide store atomic i32 0, i32* %el unordered, align 4 %iv.next = add nsw i32 %iv, -1 %loopcond = icmp slt i32 %iv, 1 br i1 %loopcond, label %loopexit, label %loop } define void @promote_latch_condition_decrementing_loop_05(i32* %p, i32* %a, i1 %cond) { ; CHECK-LABEL: @promote_latch_condition_decrementing_loop_05( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LEN:%.*]] = load i32, i32* [[P:%.*]], align 4, !range [[RNG0]] ; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]] ; CHECK: if.true: ; CHECK-NEXT: br label [[MERGE:%.*]] ; CHECK: if.false: ; CHECK-NEXT: [[LEN_MINUS_1:%.*]] = add nsw i32 [[LEN]], -1 ; CHECK-NEXT: br label [[MERGE]] ; CHECK: merge: ; CHECK-NEXT: [[IV_START:%.*]] = phi i32 [ [[LEN]], [[IF_TRUE]] ], [ [[LEN_MINUS_1]], [[IF_FALSE]] ] ; CHECK-NEXT: [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0 ; CHECK-NEXT: br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]] ; CHECK: preheader: ; CHECK-NEXT: [[TMP0:%.*]] = zext i32 [[IV_START]] to i64 ; CHECK-NEXT: br label [[LOOP:%.*]] ; CHECK: loopexit.loopexit: ; CHECK-NEXT: br label [[LOOPEXIT]] ; CHECK: loopexit: ; CHECK-NEXT: ret void ; CHECK: loop: ; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ] ; CHECK-NEXT: [[EL:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i64 [[INDVARS_IV]] ; CHECK-NEXT: store atomic i32 0, i32* [[EL]] unordered, align 4 ; CHECK-NEXT: [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1 ; CHECK-NEXT: br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]] ; entry: %len = load i32, i32* %p, align 4, !range !0 br i1 %cond, label %if.true, label %if.false if.true: br label %merge if.false: %len.minus.1 = add nsw i32 %len, -1 br label %merge merge: %iv_start = phi i32 [ %len, %if.true ], [%len.minus.1, %if.false ] %zero_check = icmp eq i32 %len, 0 br i1 %zero_check, label %loopexit, label %preheader preheader: br label %loop loopexit: ret void loop: %iv = phi i32 [ %iv.next, %loop ], [ %iv_start, %preheader ] %iv.wide = zext i32 %iv to i64 %el = getelementptr inbounds i32, i32* %a, i64 %iv.wide store atomic i32 0, i32* %el unordered, align 4 %iv.next = add nsw i32 %iv, -1 %loopcond = icmp slt i32 %iv, 1 br i1 %loopcond, label %loopexit, label %loop } !0 = !{i32 0, i32 2147483647}