1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -loop-unroll -unroll-runtime-epilog=true | FileCheck %s -check-prefix=EPILOG 3; RUN: opt < %s -S -unroll-runtime -unroll-count=2 -loop-unroll -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG 4target 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 case 7; when the backedge-count is -1. 8 9; If %N, the backedge-taken count, is -1 then %0 unsigned-overflows 10; and is 0. %xtraiter too is 0, signifying that the total trip-count 11; is divisible by 2. The prologue then branches to the unrolled loop 12; 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:%.*]], 1 18; EPILOG-NEXT: [[XTRAITER:%.*]] = and i32 [[TMP0]], 1 19; EPILOG-NEXT: [[TMP1:%.*]] = icmp ult i32 [[N]], 1 20; EPILOG-NEXT: br i1 [[TMP1]], label [[WHILE_END_UNR_LCSSA:%.*]], 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]], 1 28; EPILOG-NEXT: [[NITER_NEXT:%.*]] = add nuw nsw i32 [[NITER]], 1 29; EPILOG-NEXT: [[INC_1]] = add i32 [[INC]], 1 30; EPILOG-NEXT: [[NITER_NEXT_1]] = add i32 [[NITER_NEXT]], 1 31; EPILOG-NEXT: [[NITER_NCMP_1:%.*]] = icmp eq i32 [[NITER_NEXT_1]], [[UNROLL_ITER]] 32; EPILOG-NEXT: br i1 [[NITER_NCMP_1]], label [[WHILE_END_UNR_LCSSA_LOOPEXIT:%.*]], label [[WHILE_BODY]], !llvm.loop [[LOOP0:![0-9]+]] 33; EPILOG: while.end.unr-lcssa.loopexit: 34; EPILOG-NEXT: [[I_LCSSA_PH_PH:%.*]] = phi i32 [ [[INC]], [[WHILE_BODY]] ] 35; EPILOG-NEXT: [[I_UNR_PH:%.*]] = phi i32 [ [[INC_1]], [[WHILE_BODY]] ] 36; EPILOG-NEXT: br label [[WHILE_END_UNR_LCSSA]] 37; EPILOG: while.end.unr-lcssa: 38; EPILOG-NEXT: [[I_LCSSA_PH:%.*]] = phi i32 [ undef, [[ENTRY:%.*]] ], [ [[I_LCSSA_PH_PH]], [[WHILE_END_UNR_LCSSA_LOOPEXIT]] ] 39; EPILOG-NEXT: [[I_UNR:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[I_UNR_PH]], [[WHILE_END_UNR_LCSSA_LOOPEXIT]] ] 40; EPILOG-NEXT: [[LCMP_MOD:%.*]] = icmp ne i32 [[XTRAITER]], 0 41; EPILOG-NEXT: br i1 [[LCMP_MOD]], label [[WHILE_BODY_EPIL_PREHEADER:%.*]], label [[WHILE_END:%.*]] 42; EPILOG: while.body.epil.preheader: 43; EPILOG-NEXT: br label [[WHILE_BODY_EPIL:%.*]] 44; EPILOG: while.body.epil: 45; EPILOG-NEXT: br label [[WHILE_END]] 46; EPILOG: while.end: 47; EPILOG-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I_LCSSA_PH]], [[WHILE_END_UNR_LCSSA]] ], [ [[I_UNR]], [[WHILE_BODY_EPIL]] ] 48; EPILOG-NEXT: ret i32 [[I_LCSSA]] 49; 50; PROLOG-LABEL: @foo( 51; PROLOG-NEXT: entry: 52; PROLOG-NEXT: [[TMP0:%.*]] = add i32 [[N:%.*]], 1 53; PROLOG-NEXT: [[XTRAITER:%.*]] = and i32 [[TMP0]], 1 54; PROLOG-NEXT: [[LCMP_MOD:%.*]] = icmp ne i32 [[XTRAITER]], 0 55; PROLOG-NEXT: br i1 [[LCMP_MOD]], label [[WHILE_BODY_PROL_PREHEADER:%.*]], label [[WHILE_BODY_PROL_LOOPEXIT:%.*]] 56; PROLOG: while.body.prol.preheader: 57; PROLOG-NEXT: br label [[WHILE_BODY_PROL:%.*]] 58; PROLOG: while.body.prol: 59; PROLOG-NEXT: br label [[WHILE_BODY_PROL_LOOPEXIT]] 60; PROLOG: while.body.prol.loopexit: 61; PROLOG-NEXT: [[I_LCSSA_UNR:%.*]] = phi i32 [ undef, [[ENTRY:%.*]] ], [ 0, [[WHILE_BODY_PROL]] ] 62; PROLOG-NEXT: [[I_UNR:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ 1, [[WHILE_BODY_PROL]] ] 63; PROLOG-NEXT: [[TMP1:%.*]] = icmp ult i32 [[N]], 1 64; PROLOG-NEXT: br i1 [[TMP1]], label [[WHILE_END:%.*]], label [[ENTRY_NEW:%.*]] 65; PROLOG: entry.new: 66; PROLOG-NEXT: br label [[WHILE_BODY:%.*]] 67; PROLOG: while.body: 68; PROLOG-NEXT: [[I:%.*]] = phi i32 [ [[I_UNR]], [[ENTRY_NEW]] ], [ [[INC_1:%.*]], [[WHILE_BODY]] ] 69; PROLOG-NEXT: [[INC:%.*]] = add i32 [[I]], 1 70; PROLOG-NEXT: [[CMP_1:%.*]] = icmp eq i32 [[INC]], [[N]] 71; PROLOG-NEXT: [[INC_1]] = add i32 [[INC]], 1 72; PROLOG-NEXT: br i1 [[CMP_1]], label [[WHILE_END_UNR_LCSSA:%.*]], label [[WHILE_BODY]], !llvm.loop [[LOOP0:![0-9]+]] 73; PROLOG: while.end.unr-lcssa: 74; PROLOG-NEXT: [[I_LCSSA_PH:%.*]] = phi i32 [ [[INC]], [[WHILE_BODY]] ] 75; PROLOG-NEXT: br label [[WHILE_END]] 76; PROLOG: while.end: 77; PROLOG-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I_LCSSA_UNR]], [[WHILE_BODY_PROL_LOOPEXIT]] ], [ [[I_LCSSA_PH]], [[WHILE_END_UNR_LCSSA]] ] 78; PROLOG-NEXT: ret i32 [[I_LCSSA]] 79; 80entry: 81 br label %while.body 82 83while.body: ; preds = %while.body, %entry 84 %i = phi i32 [ 0, %entry ], [ %inc, %while.body ] 85 %cmp = icmp eq i32 %i, %N 86 %inc = add i32 %i, 1 87 br i1 %cmp, label %while.end, label %while.body 88 89while.end: ; preds = %while.body 90 ret i32 %i 91} 92