[llvm] [VPlan] Introduce VPlanConstantFolder (PR #125365)
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 7 13:39:01 PDT 2025
================
@@ -0,0 +1,360 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=loop-vectorize -force-vector-width=4 -S %s | FileCheck %s
+
+define void @const_fold_ptradd(ptr %dst, i64 %d) {
+; CHECK-LABEL: define void @const_fold_ptradd(
+; CHECK-SAME: ptr [[DST:%.*]], i64 [[D:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr i16, ptr [[DST]], i64 0
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: store i16 0, ptr [[TMP0]], align 2
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[INDEX_NEXT]], 100
+; CHECK-NEXT: br i1 [[TMP1]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: br i1 false, label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 100, %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: br i1 true, label %[[LOOP_LATCH]], label %[[ELSE:.*]]
+; CHECK: [[ELSE]]:
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[CONST_0:%.*]] = phi i64 [ [[D]], %[[ELSE]] ], [ 0, %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr i16, ptr [[DST]], i64 [[CONST_0]]
+; CHECK-NEXT: store i16 0, ptr [[GEP]], align 2
+; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[IV_NEXT]], 101
+; CHECK-NEXT: br i1 [[CMP]], label %[[LOOP_HEADER]], label %[[EXIT]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop.header
+
+loop.header: ; preds = %loop.latch, %entry
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ br i1 true, label %loop.latch, label %else
+
+else:
+ br label %loop.latch
+
+loop.latch:
+ %const.0 = phi i64 [ %d, %else ], [ 0, %loop.header ]
+ %gep = getelementptr i16, ptr %dst, i64 %const.0
+ store i16 0, ptr %gep, align 2
+ %iv.next = add i64 %iv, 1
+ %cmp = icmp ult i64 %iv.next, 101
+ br i1 %cmp, label %loop.header, label %exit
+
+exit:
+ ret void
+}
+
+define void @const_fold_inbounds_ptradd(ptr %dst, i64 %d) {
+; CHECK-LABEL: define void @const_fold_inbounds_ptradd(
+; CHECK-SAME: ptr [[DST:%.*]], i64 [[D:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds i16, ptr [[DST]], i64 0
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: store i16 0, ptr [[TMP0]], align 2
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[INDEX_NEXT]], 100
+; CHECK-NEXT: br i1 [[TMP1]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: br i1 false, label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 100, %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: br i1 true, label %[[LOOP_LATCH]], label %[[ELSE:.*]]
+; CHECK: [[ELSE]]:
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[CONST_0:%.*]] = phi i64 [ [[D]], %[[ELSE]] ], [ 0, %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i16, ptr [[DST]], i64 [[CONST_0]]
+; CHECK-NEXT: store i16 0, ptr [[GEP]], align 2
+; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[IV_NEXT]], 101
+; CHECK-NEXT: br i1 [[CMP]], label %[[LOOP_HEADER]], label %[[EXIT]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop.header
+
+loop.header: ; preds = %loop.latch, %entry
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ br i1 true, label %loop.latch, label %else
+
+else:
+ br label %loop.latch
+
+loop.latch:
+ %const.0 = phi i64 [ %d, %else ], [ 0, %loop.header ]
+ %gep = getelementptr inbounds i16, ptr %dst, i64 %const.0
+ store i16 0, ptr %gep, align 2
+ %iv.next = add i64 %iv, 1
+ %cmp = icmp ult i64 %iv.next, 101
+ br i1 %cmp, label %loop.header, label %exit
+
+exit:
+ ret void
+}
+
+define void @const_fold_select(ptr %dst, i64 %d) {
+; CHECK-LABEL: define void @const_fold_select(
+; CHECK-SAME: ptr [[DST:%.*]], i64 [[D:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK: [[VECTOR_PH]]:
+; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[D]], i64 0
+; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-NEXT: [[TMP0:%.*]] = or <4 x i64> [[BROADCAST_SPLAT]], splat (i64 1)
+; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
+; CHECK: [[VECTOR_BODY]]:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT: [[TMP3:%.*]] = extractelement <4 x i64> [[TMP0]], i32 0
+; CHECK-NEXT: store i64 [[TMP3]], ptr [[DST]], align 8
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], 100
+; CHECK-NEXT: br i1 [[TMP4]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK: [[MIDDLE_BLOCK]]:
+; CHECK-NEXT: br i1 false, label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK: [[SCALAR_PH]]:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 100, %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
+; CHECK: [[LOOP_HEADER]]:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT: br i1 true, label %[[LOOP_LATCH]], label %[[ELSE:.*]]
+; CHECK: [[ELSE]]:
+; CHECK-NEXT: br label %[[LOOP_LATCH]]
+; CHECK: [[LOOP_LATCH]]:
+; CHECK-NEXT: [[CONST_1:%.*]] = phi i64 [ [[D]], %[[ELSE]] ], [ 1, %[[LOOP_HEADER]] ]
+; CHECK-NEXT: [[OR:%.*]] = or i64 [[D]], [[CONST_1]]
+; CHECK-NEXT: store i64 [[OR]], ptr [[DST]], align 8
+; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[IV_NEXT]], 101
+; CHECK-NEXT: br i1 [[CMP]], label %[[LOOP_HEADER]], label %[[EXIT]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop.header
+
+loop.header: ; preds = %loop.latch, %entry
+ %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+ br i1 true, label %loop.latch, label %else
+
+else:
+ br label %loop.latch
+
+loop.latch:
+ %const.1 = phi i64 [ %d, %else ], [ 1, %loop.header ]
+ %or = or i64 %d, %const.1
+ store i64 %or, ptr %dst, align 8
+ %iv.next = add i64 %iv, 1
+ %cmp = icmp ult i64 %iv.next, 101
----------------
fhahn wrote:
might be worth using `100` instead, so the scalar loop doesn't need to execute?
https://github.com/llvm/llvm-project/pull/125365
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