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
51 lines
2.4 KiB
LLVM
51 lines
2.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 5
|
|
; RUN: opt -passes=loop-vectorize -S %s | FileCheck %s
|
|
|
|
; There could be more than one LCSSA PHIs in loop exit block.
|
|
define i16 @duplicate_lcssa(i16 %val) {
|
|
; CHECK-LABEL: define i16 @duplicate_lcssa(
|
|
; CHECK-SAME: i16 [[VAL:%.*]]) {
|
|
; CHECK-NEXT: [[ENTRY:.*:]]
|
|
; CHECK-NEXT: br label %[[VECTOR_PH:.*]]
|
|
; CHECK: [[VECTOR_PH]]:
|
|
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
|
|
; CHECK: [[VECTOR_BODY]]:
|
|
; CHECK-NEXT: [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
|
|
; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i16> [ <i16 0, i16 -1, i16 -2, i16 -3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
|
|
; CHECK-NEXT: [[TMP0:%.*]] = sub nsw <4 x i16> [[VEC_IND]], splat (i16 1)
|
|
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
|
|
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i16> [[VEC_IND]], splat (i16 -4)
|
|
; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i32 [[INDEX_NEXT]], 65536
|
|
; CHECK-NEXT: br i1 [[TMP1]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
|
|
; CHECK: [[MIDDLE_BLOCK]]:
|
|
; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI1:%.*]] = extractelement <4 x i16> [[TMP0]], i32 2
|
|
; CHECK-NEXT: br label %[[EXIT:.*]]
|
|
; CHECK: [[SCALAR_PH:.*]]:
|
|
; CHECK-NEXT: br label %[[LOOP:.*]]
|
|
; CHECK: [[LOOP]]:
|
|
; CHECK-NEXT: [[IV:%.*]] = phi i16 [ 0, %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
|
|
; CHECK-NEXT: [[RES:%.*]] = phi i16 [ [[VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT]], %[[LOOP]] ]
|
|
; CHECK-NEXT: [[IV_NEXT]] = sub nsw i16 [[IV]], 1
|
|
; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp ne i16 [[IV_NEXT]], 0
|
|
; CHECK-NEXT: br i1 [[EXIT_COND]], label %[[LOOP]], label %[[EXIT]]
|
|
; CHECK: [[EXIT]]:
|
|
; CHECK-NEXT: [[LCSSA_1:%.*]] = phi i16 [ [[RES]], %[[LOOP]] ], [ [[VECTOR_RECUR_EXTRACT_FOR_PHI1]], %[[MIDDLE_BLOCK]] ]
|
|
; CHECK-NEXT: [[LCSSA_2:%.*]] = phi i16 [ [[RES]], %[[LOOP]] ], [ [[VECTOR_RECUR_EXTRACT_FOR_PHI1]], %[[MIDDLE_BLOCK]] ]
|
|
; CHECK-NEXT: ret i16 [[LCSSA_2]]
|
|
;
|
|
entry:
|
|
br label %loop
|
|
|
|
loop:
|
|
%iv = phi i16 [ 0, %entry ], [ %iv.next, %loop ]
|
|
%res = phi i16 [ %val, %entry ], [ %iv.next, %loop ]
|
|
%iv.next = sub nsw i16 %iv, 1
|
|
%exit.cond = icmp ne i16 %iv.next, 0
|
|
br i1 %exit.cond, label %loop, label %exit
|
|
|
|
exit:
|
|
%lcssa.1 = phi i16 [ %res, %loop ]
|
|
%lcssa.2 = phi i16 [ %res, %loop ]
|
|
ret i16 %lcssa.2
|
|
}
|