50b9ca4dda
After https://github.com/llvm/llvm-project/pull/153643, there may be a BranchOnCond with constant condition in the entry block. Simplify those in removeBranchOnConst. This removes a number of redundant conditional branch from entry blocks. In some cases, it may also make the original scalar loop unreachable, because we know it will never execute. In that case, we need to remove the loop from LoopInfo, because all unreachable blocks may dominate each other, making LoopInfo invalid. In those cases, we can also completely remove the loop, for which I'll share a follow-up patch. Depends on https://github.com/llvm/llvm-project/pull/153643. PR: https://github.com/llvm/llvm-project/pull/154510
98 lines
3.9 KiB
LLVM
98 lines
3.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --filter-out-after "vector.ph:" --version 5
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; RUN: opt %s -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S | FileCheck %s
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; RUN: opt %s -passes=loop-vectorize -force-vector-interleave=2 -force-vector-width=4 -S | FileCheck %s -check-prefix=UNROLL
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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@b = common global [1000 x i32] zeroinitializer, align 16
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@c = common global [1000 x i32] zeroinitializer, align 16
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@a = common global [1000 x i32] zeroinitializer, align 16
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; Generate min.iters.check to skip the vector loop and jump to scalar.ph directly when loop iteration number is less than VF * UF.
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define void @foo(i64 %N) {
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; CHECK-LABEL: define void @foo(
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; CHECK-SAME: i64 [[N:%.*]]) {
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; CHECK-NEXT: [[ENTRY:.*:]]
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; CHECK-NEXT: [[C:%.*]] = icmp sgt i64 [[N]], 0
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; CHECK-NEXT: br i1 [[C]], label %[[LOOP_PREHEADER:.*]], [[EXIT:label %.*]]
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; CHECK: [[LOOP_PREHEADER]]:
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; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
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; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
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; CHECK: [[VECTOR_PH]]:
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;
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; UNROLL-LABEL: define void @foo(
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; UNROLL-SAME: i64 [[N:%.*]]) {
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; UNROLL-NEXT: [[ENTRY:.*:]]
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; UNROLL-NEXT: [[C:%.*]] = icmp sgt i64 [[N]], 0
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; UNROLL-NEXT: br i1 [[C]], label %[[LOOP_PREHEADER:.*]], [[EXIT:label %.*]]
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; UNROLL: [[LOOP_PREHEADER]]:
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; UNROLL-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 8
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; UNROLL-NEXT: br i1 [[MIN_ITERS_CHECK]], [[SCALAR_PH:label %.*]], label %[[VECTOR_PH:.*]]
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; UNROLL: [[VECTOR_PH]]:
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;
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entry:
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%c = icmp sgt i64 %N, 0
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br i1 %c, label %loop, label %exit
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loop:
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%iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
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%arrayidx = getelementptr inbounds [1000 x i32], ptr @b, i64 0, i64 %iv
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%tmp = load i32, ptr %arrayidx, align 4
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%arrayidx1 = getelementptr inbounds [1000 x i32], ptr @c, i64 0, i64 %iv
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%tmp1 = load i32, ptr %arrayidx1, align 4
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%add = add nsw i32 %tmp1, %tmp
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%arrayidx2 = getelementptr inbounds [1000 x i32], ptr @a, i64 0, i64 %iv
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store i32 %add, ptr %arrayidx2, align 4
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%iv.next = add nuw nsw i64 %iv, 1
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%ec = icmp eq i64 %iv.next, %N
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br i1 %ec, label %exit, label %loop
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exit:
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ret void
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}
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define void @min_iters_known_via_loop_guards_add(i32 %start, i32 %end, ptr %src) {
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; CHECK-LABEL: define void @min_iters_known_via_loop_guards_add(
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; CHECK-SAME: i32 [[START:%.*]], i32 [[END:%.*]], ptr [[SRC:%.*]]) {
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; CHECK-NEXT: [[ENTRY:.*:]]
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; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[END]], [[START]]
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; CHECK-NEXT: [[PRE:%.*]] = icmp sgt i32 [[SUB]], 100
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; CHECK-NEXT: call void @llvm.assume(i1 [[PRE]])
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; CHECK-NEXT: [[ADD_1:%.*]] = add i32 [[SUB]], 1
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; CHECK-NEXT: [[IV_START:%.*]] = zext i32 [[ADD_1]] to i64
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; CHECK-NEXT: [[TMP0:%.*]] = sub i64 101, [[IV_START]]
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; CHECK-NEXT: br label %[[VECTOR_PH:.*]]
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; CHECK: [[VECTOR_PH]]:
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;
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; UNROLL-LABEL: define void @min_iters_known_via_loop_guards_add(
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; UNROLL-SAME: i32 [[START:%.*]], i32 [[END:%.*]], ptr [[SRC:%.*]]) {
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; UNROLL-NEXT: [[ENTRY:.*:]]
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; UNROLL-NEXT: [[SUB:%.*]] = sub i32 [[END]], [[START]]
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; UNROLL-NEXT: [[PRE:%.*]] = icmp sgt i32 [[SUB]], 100
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; UNROLL-NEXT: call void @llvm.assume(i1 [[PRE]])
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; UNROLL-NEXT: [[ADD_1:%.*]] = add i32 [[SUB]], 1
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; UNROLL-NEXT: [[IV_START:%.*]] = zext i32 [[ADD_1]] to i64
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; UNROLL-NEXT: [[TMP0:%.*]] = sub i64 101, [[IV_START]]
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; UNROLL-NEXT: br label %[[VECTOR_PH:.*]]
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; UNROLL: [[VECTOR_PH]]:
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;
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entry:
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%sub = sub i32 %end, %start
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%pre = icmp sgt i32 %sub, 100
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call void @llvm.assume(i1 %pre)
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%add.1 = add i32 %sub, 1
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%iv.start = zext i32 %add.1 to i64
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br label %loop
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loop:
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%iv = phi i64 [ %iv.start, %entry ], [ %iv.next, %loop ]
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%gep = getelementptr inbounds i64, ptr %src, i64 %iv
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store i64 %iv, ptr %gep
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%iv.next = add i64 %iv, 1
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%ec = icmp eq i64 %iv, 100
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br i1 %ec, label %exit, label %loop
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exit:
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ret void
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}
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