[llvm] 6ecc992 - [LoopUnroll] Test multi-exit runtime unrolling with predictable exit (NFC)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Sun Jun 13 09:48:48 PDT 2021
Author: Nikita Popov
Date: 2021-06-13T18:48:38+02:00
New Revision: 6ecc99210cdc87cff7d47484695b812196a9e905
URL: https://github.com/llvm/llvm-project/commit/6ecc99210cdc87cff7d47484695b812196a9e905
DIFF: https://github.com/llvm/llvm-project/commit/6ecc99210cdc87cff7d47484695b812196a9e905.diff
LOG: [LoopUnroll] Test multi-exit runtime unrolling with predictable exit (NFC)
The (prior to prologue insertion) predictable exit shouldn't get
folded here. Make sure it isn't...
Added:
llvm/test/Transforms/LoopUnroll/runtime-loop-known-exit.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/LoopUnroll/runtime-loop-known-exit.ll b/llvm/test/Transforms/LoopUnroll/runtime-loop-known-exit.ll
new file mode 100644
index 0000000000000..48036b16840df
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/runtime-loop-known-exit.ll
@@ -0,0 +1,107 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -loop-unroll -unroll-runtime -unroll-runtime-multi-exit < %s | FileCheck %s
+
+; This loop has a known trip count on the non-latch exit. When performing
+; runtime unrolling (at least when using a prologue rather than epilogue) we
+; should not fold that exit based on known trip count information prior to
+; prologue insertion, as that may change the trip count for the modified loop.
+
+define void @test(i32 %s, i32 %n) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N2:%.*]] = add i32 [[S:%.*]], 123
+; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[N:%.*]], 1
+; CHECK-NEXT: [[TMP1:%.*]] = sub i32 [[TMP0]], [[S]]
+; CHECK-NEXT: [[TMP2:%.*]] = sub i32 [[N]], [[S]]
+; CHECK-NEXT: [[XTRAITER:%.*]] = and i32 [[TMP1]], 7
+; CHECK-NEXT: [[LCMP_MOD:%.*]] = icmp ne i32 [[XTRAITER]], 0
+; CHECK-NEXT: br i1 [[LCMP_MOD]], label [[LOOP_PROL_PREHEADER:%.*]], label [[LOOP_PROL_LOOPEXIT:%.*]]
+; CHECK: loop.prol.preheader:
+; CHECK-NEXT: br label [[LOOP_PROL:%.*]]
+; CHECK: loop.prol:
+; CHECK-NEXT: [[I_PROL:%.*]] = phi i32 [ [[S]], [[LOOP_PROL_PREHEADER]] ], [ [[I_INC_PROL:%.*]], [[LATCH_PROL:%.*]] ]
+; CHECK-NEXT: [[PROL_ITER:%.*]] = phi i32 [ [[XTRAITER]], [[LOOP_PROL_PREHEADER]] ], [ [[PROL_ITER_SUB:%.*]], [[LATCH_PROL]] ]
+; CHECK-NEXT: [[C1_PROL:%.*]] = icmp eq i32 [[I_PROL]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_PROL]], label [[EXIT1_LOOPEXIT1:%.*]], label [[LATCH_PROL]]
+; CHECK: latch.prol:
+; CHECK-NEXT: [[C2_PROL:%.*]] = icmp eq i32 [[I_PROL]], [[N]]
+; CHECK-NEXT: [[I_INC_PROL]] = add i32 [[I_PROL]], 1
+; CHECK-NEXT: [[PROL_ITER_SUB]] = sub i32 [[PROL_ITER]], 1
+; CHECK-NEXT: [[PROL_ITER_CMP:%.*]] = icmp ne i32 [[PROL_ITER_SUB]], 0
+; CHECK-NEXT: br i1 [[PROL_ITER_CMP]], label [[LOOP_PROL]], label [[LOOP_PROL_LOOPEXIT_UNR_LCSSA:%.*]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK: loop.prol.loopexit.unr-lcssa:
+; CHECK-NEXT: [[I_UNR_PH:%.*]] = phi i32 [ [[I_INC_PROL]], [[LATCH_PROL]] ]
+; CHECK-NEXT: br label [[LOOP_PROL_LOOPEXIT]]
+; CHECK: loop.prol.loopexit:
+; CHECK-NEXT: [[I_UNR:%.*]] = phi i32 [ [[S]], [[ENTRY:%.*]] ], [ [[I_UNR_PH]], [[LOOP_PROL_LOOPEXIT_UNR_LCSSA]] ]
+; CHECK-NEXT: [[TMP3:%.*]] = icmp ult i32 [[TMP2]], 7
+; CHECK-NEXT: br i1 [[TMP3]], label [[EXIT2:%.*]], label [[ENTRY_NEW:%.*]]
+; CHECK: entry.new:
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_UNR]], [[ENTRY_NEW]] ], [ [[I_INC_7:%.*]], [[LATCH_7:%.*]] ]
+; CHECK-NEXT: [[C1:%.*]] = icmp eq i32 [[I]], [[N2]]
+; CHECK-NEXT: br i1 [[C1]], label [[EXIT1_LOOPEXIT:%.*]], label [[LATCH:%.*]]
+; CHECK: latch:
+; CHECK-NEXT: [[I_INC:%.*]] = add i32 [[I]], 1
+; CHECK-NEXT: [[C1_1:%.*]] = icmp eq i32 [[I_INC]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_1]], label [[EXIT1_LOOPEXIT]], label [[LATCH_1:%.*]]
+; CHECK: exit1.loopexit:
+; CHECK-NEXT: br label [[EXIT1:%.*]]
+; CHECK: exit1.loopexit1:
+; CHECK-NEXT: br label [[EXIT1]]
+; CHECK: exit1:
+; CHECK-NEXT: ret void
+; CHECK: exit2.unr-lcssa:
+; CHECK-NEXT: br label [[EXIT2]]
+; CHECK: exit2:
+; CHECK-NEXT: ret void
+; CHECK: latch.1:
+; CHECK-NEXT: [[I_INC_1:%.*]] = add i32 [[I_INC]], 1
+; CHECK-NEXT: [[C1_2:%.*]] = icmp eq i32 [[I_INC_1]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_2]], label [[EXIT1_LOOPEXIT]], label [[LATCH_2:%.*]]
+; CHECK: latch.2:
+; CHECK-NEXT: [[I_INC_2:%.*]] = add i32 [[I_INC_1]], 1
+; CHECK-NEXT: [[C1_3:%.*]] = icmp eq i32 [[I_INC_2]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_3]], label [[EXIT1_LOOPEXIT]], label [[LATCH_3:%.*]]
+; CHECK: latch.3:
+; CHECK-NEXT: [[I_INC_3:%.*]] = add i32 [[I_INC_2]], 1
+; CHECK-NEXT: [[C1_4:%.*]] = icmp eq i32 [[I_INC_3]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_4]], label [[EXIT1_LOOPEXIT]], label [[LATCH_4:%.*]]
+; CHECK: latch.4:
+; CHECK-NEXT: [[I_INC_4:%.*]] = add i32 [[I_INC_3]], 1
+; CHECK-NEXT: [[C1_5:%.*]] = icmp eq i32 [[I_INC_4]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_5]], label [[EXIT1_LOOPEXIT]], label [[LATCH_5:%.*]]
+; CHECK: latch.5:
+; CHECK-NEXT: [[I_INC_5:%.*]] = add i32 [[I_INC_4]], 1
+; CHECK-NEXT: [[C1_6:%.*]] = icmp eq i32 [[I_INC_5]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_6]], label [[EXIT1_LOOPEXIT]], label [[LATCH_6:%.*]]
+; CHECK: latch.6:
+; CHECK-NEXT: [[I_INC_6:%.*]] = add i32 [[I_INC_5]], 1
+; CHECK-NEXT: [[C1_7:%.*]] = icmp eq i32 [[I_INC_6]], [[N2]]
+; CHECK-NEXT: br i1 [[C1_7]], label [[EXIT1_LOOPEXIT]], label [[LATCH_7]]
+; CHECK: latch.7:
+; CHECK-NEXT: [[C2_7:%.*]] = icmp eq i32 [[I_INC_6]], [[N]]
+; CHECK-NEXT: [[I_INC_7]] = add i32 [[I_INC_6]], 1
+; CHECK-NEXT: br i1 [[C2_7]], label [[EXIT2_UNR_LCSSA:%.*]], label [[LOOP]]
+;
+entry:
+ %n2 = add i32 %s, 123
+ br label %loop
+
+loop:
+ %i = phi i32 [ %s, %entry], [ %i.inc, %latch ]
+ %c1 = icmp eq i32 %i, %n2
+ br i1 %c1, label %exit1, label %latch
+
+latch:
+ %c2 = icmp eq i32 %i, %n
+ %i.inc = add i32 %i, 1
+ br i1 %c2, label %exit2, label %loop
+
+exit1:
+ ret void
+
+exit2:
+ ret void
+}
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