diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h --- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h +++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h @@ -185,7 +185,9 @@ } unsigned getMaxInterleaveFactor(unsigned VF) { - return ST->getMaxInterleaveFactor(); + // If the loop will not be vectorized, don't interleave the loop. + // Let regular unroll to unroll the loop. + return VF == 1 ? 1 : ST->getMaxInterleaveFactor(); } }; diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/unroll-in-loop-vectorizer.ll b/llvm/test/Transforms/LoopVectorize/RISCV/unroll-in-loop-vectorizer.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/RISCV/unroll-in-loop-vectorizer.ll @@ -0,0 +1,43 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -S -mtriple=riscv64 -mattr=+experimental-v -loop-vectorize < %s | FileCheck %s + +; Make sure we don't unroll scalar loops in the loop vectorizer. +; +define void @small_loop(i32* nocapture %inArray, i32 %size) nounwind { +; CHECK-LABEL: @small_loop( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[SIZE:%.*]], 0 +; CHECK-NEXT: br i1 [[TMP0]], label [[LOOP_PREHEADER:%.*]], label [[EXIT:%.*]] +; CHECK: loop.preheader: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV1:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ] +; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, i32* [[INARRAY:%.*]], i32 [[IV]] +; CHECK-NEXT: [[TMP2:%.*]] = load i32, i32* [[TMP1]], align 4 +; CHECK-NEXT: [[TMP3:%.*]] = add nsw i32 [[TMP2]], 6 +; CHECK-NEXT: store i32 [[TMP3]], i32* [[TMP1]], align 4 +; CHECK-NEXT: [[IV1]] = add i32 [[IV]], 1 +; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[IV1]], [[SIZE]] +; CHECK-NEXT: br i1 [[COND]], label [[EXIT_LOOPEXIT:%.*]], label [[LOOP]] +; CHECK: exit.loopexit: +; CHECK-NEXT: br label [[EXIT]] +; CHECK: exit: +; CHECK-NEXT: ret void +; +entry: + %0 = icmp sgt i32 %size, 0 + br i1 %0, label %loop, label %exit + +loop: ; preds = %entry, %loop + %iv = phi i32 [ %iv1, %loop ], [ 0, %entry ] + %1 = getelementptr inbounds i32, i32* %inArray, i32 %iv + %2 = load i32, i32* %1, align 4 + %3 = add nsw i32 %2, 6 + store i32 %3, i32* %1, align 4 + %iv1 = add i32 %iv, 1 + %cond = icmp eq i32 %iv1, %size + br i1 %cond, label %exit, label %loop + +exit: ; preds = %loop, %entry + ret void +}