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1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py2; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -passes=loop-unroll -unroll-runtime-epilog=true | FileCheck %s -check-prefix=EPILOG3; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -passes=loop-unroll -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG4target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"5 6; This test case documents how runtime loop unrolling handles the case7; when the backedge-count is -1.8 9; If %N, the backedge-taken count, is -1 then %0 unsigned-overflows10; and is 0. %xtraiter too is 0, signifying that the total trip-count11; is divisible by 2. The prologue then branches to the unrolled loop12; and executes the 2^32 iterations there, in groups of 2.13 14define i32 @foo(i32 %N) {15; EPILOG-LABEL: @foo(16; EPILOG-NEXT: entry:17; EPILOG-NEXT: [[TMP0:%.*]] = add i32 [[N:%.*]], 118; EPILOG-NEXT: [[XTRAITER:%.*]] = and i32 [[TMP0]], 119; EPILOG-NEXT: [[TMP1:%.*]] = icmp ult i32 [[N]], 120; EPILOG-NEXT: br i1 [[TMP1]], label [[WHILE_BODY_EPIL_PREHEADER:%.*]], label [[ENTRY_NEW:%.*]]21; EPILOG: entry.new:22; EPILOG-NEXT: [[UNROLL_ITER:%.*]] = sub i32 [[TMP0]], [[XTRAITER]]23; EPILOG-NEXT: br label [[WHILE_BODY:%.*]]24; EPILOG: while.body:25; EPILOG-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY_NEW]] ], [ [[INC_1:%.*]], [[WHILE_BODY]] ]26; EPILOG-NEXT: [[NITER:%.*]] = phi i32 [ 0, [[ENTRY_NEW]] ], [ [[NITER_NEXT_1:%.*]], [[WHILE_BODY]] ]27; EPILOG-NEXT: [[INC:%.*]] = add nuw nsw i32 [[I]], 128; EPILOG-NEXT: [[INC_1]] = add i32 [[I]], 229; EPILOG-NEXT: [[NITER_NEXT_1]] = add i32 [[NITER]], 230; EPILOG-NEXT: [[NITER_NCMP_1:%.*]] = icmp eq i32 [[NITER_NEXT_1]], [[UNROLL_ITER]]31; EPILOG-NEXT: br i1 [[NITER_NCMP_1]], label [[WHILE_END_UNR_LCSSA:%.*]], label [[WHILE_BODY]], !llvm.loop [[LOOP0:![0-9]+]]32; EPILOG: while.end.unr-lcssa:33; EPILOG-NEXT: [[I_LCSSA_PH_PH:%.*]] = phi i32 [ [[INC]], [[WHILE_BODY]] ]34; EPILOG-NEXT: [[I_UNR_PH:%.*]] = phi i32 [ [[INC_1]], [[WHILE_BODY]] ]35; EPILOG-NEXT: [[LCMP_MOD:%.*]] = icmp ne i32 [[XTRAITER]], 036; EPILOG-NEXT: br i1 [[LCMP_MOD]], label [[WHILE_BODY_EPIL_PREHEADER]], label [[WHILE_END:%.*]]37; EPILOG: while.body.epil.preheader:38; EPILOG-NEXT: [[I_EPIL_INIT:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_UNR_PH]], [[WHILE_END_UNR_LCSSA]] ]39; EPILOG-NEXT: [[LCMP_MOD2:%.*]] = icmp ne i32 [[XTRAITER]], 040; EPILOG-NEXT: call void @llvm.assume(i1 [[LCMP_MOD2]])41; EPILOG-NEXT: br label [[WHILE_BODY_EPIL:%.*]]42; EPILOG: while.body.epil:43; EPILOG-NEXT: br label [[WHILE_END]]44; EPILOG: while.end:45; EPILOG-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I_LCSSA_PH_PH]], [[WHILE_END_UNR_LCSSA]] ], [ [[I_EPIL_INIT]], [[WHILE_BODY_EPIL]] ]46; EPILOG-NEXT: ret i32 [[I_LCSSA]]47;48; PROLOG-LABEL: @foo(49; PROLOG-NEXT: entry:50; PROLOG-NEXT: [[TMP0:%.*]] = add i32 [[N:%.*]], 151; PROLOG-NEXT: [[XTRAITER:%.*]] = and i32 [[TMP0]], 152; PROLOG-NEXT: [[LCMP_MOD:%.*]] = icmp ne i32 [[XTRAITER]], 053; PROLOG-NEXT: br i1 [[LCMP_MOD]], label [[WHILE_BODY_PROL_PREHEADER:%.*]], label [[WHILE_BODY_PROL_LOOPEXIT:%.*]]54; PROLOG: while.body.prol.preheader:55; PROLOG-NEXT: br label [[WHILE_BODY_PROL:%.*]]56; PROLOG: while.body.prol:57; PROLOG-NEXT: br label [[WHILE_BODY_PROL_LOOPEXIT]]58; PROLOG: while.body.prol.loopexit:59; PROLOG-NEXT: [[I_LCSSA_UNR:%.*]] = phi i32 [ poison, [[ENTRY:%.*]] ], [ 0, [[WHILE_BODY_PROL]] ]60; PROLOG-NEXT: [[I_UNR:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ 1, [[WHILE_BODY_PROL]] ]61; PROLOG-NEXT: [[TMP1:%.*]] = icmp ult i32 [[N]], 162; PROLOG-NEXT: br i1 [[TMP1]], label [[WHILE_END:%.*]], label [[ENTRY_NEW:%.*]]63; PROLOG: entry.new:64; PROLOG-NEXT: br label [[WHILE_BODY:%.*]]65; PROLOG: while.body:66; PROLOG-NEXT: [[I:%.*]] = phi i32 [ [[I_UNR]], [[ENTRY_NEW]] ], [ [[INC_1:%.*]], [[WHILE_BODY]] ]67; PROLOG-NEXT: [[INC:%.*]] = add i32 [[I]], 168; PROLOG-NEXT: [[CMP_1:%.*]] = icmp eq i32 [[INC]], [[N]]69; PROLOG-NEXT: [[INC_1]] = add i32 [[I]], 270; PROLOG-NEXT: br i1 [[CMP_1]], label [[WHILE_END_UNR_LCSSA:%.*]], label [[WHILE_BODY]], !llvm.loop [[LOOP0:![0-9]+]]71; PROLOG: while.end.unr-lcssa:72; PROLOG-NEXT: [[I_LCSSA_PH:%.*]] = phi i32 [ [[INC]], [[WHILE_BODY]] ]73; PROLOG-NEXT: br label [[WHILE_END]]74; PROLOG: while.end:75; PROLOG-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I_LCSSA_UNR]], [[WHILE_BODY_PROL_LOOPEXIT]] ], [ [[I_LCSSA_PH]], [[WHILE_END_UNR_LCSSA]] ]76; PROLOG-NEXT: ret i32 [[I_LCSSA]]77;78entry:79 br label %while.body80 81while.body: ; preds = %while.body, %entry82 %i = phi i32 [ 0, %entry ], [ %inc, %while.body ]83 %cmp = icmp eq i32 %i, %N84 %inc = add i32 %i, 185 br i1 %cmp, label %while.end, label %while.body86 87while.end: ; preds = %while.body88 ret i32 %i89}90