[llvm] [LV] Bundle sub reductions into VPExpressionRecipe (PR #147255)
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 20 07:53:04 PDT 2025
================
@@ -416,3 +416,146 @@ exit:
%r.0.lcssa = phi i64 [ %rdx.next, %loop ]
ret i64 %r.0.lcssa
}
+
+define i32 @print_mulacc_sub(ptr %a, ptr %b) {
+; CHECK: VPlan 'Initial VPlan for VF={4},UF>=1' {
+; CHECK-NEXT: Live-in vp<%0> = VF
+; CHECK-NEXT: Live-in vp<%1> = VF * UF
+; CHECK-NEXT: Live-in vp<%2> = vector-trip-count
+; CHECK-NEXT: Live-in ir<1024> = original trip-count
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<entry>:
+; CHECK-NEXT: Successor(s): scalar.ph, vector.ph
+; CHECK-EMPTY:
+; CHECK-NEXT: vector.ph:
+; CHECK-NEXT: EMIT vp<%3> = reduction-start-vector ir<0>, ir<0>, ir<1>
+; CHECK-NEXT: Successor(s): vector loop
+; CHECK-EMPTY:
+; CHECK-NEXT: <x1> vector loop: {
+; CHECK-NEXT: vector.body:
+; CHECK-NEXT: EMIT vp<%4> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
+; CHECK-NEXT: WIDEN-REDUCTION-PHI ir<%accum> = phi vp<%3>, vp<%8>
+; CHECK-NEXT: vp<%5> = SCALAR-STEPS vp<%4>, ir<1>, vp<%0>
+; CHECK-NEXT: CLONE ir<%gep.a> = getelementptr ir<%a>, vp<%5>
+; CHECK-NEXT: vp<%6> = vector-pointer ir<%gep.a>
+; CHECK-NEXT: WIDEN ir<%load.a> = load vp<%6>
+; CHECK-NEXT: CLONE ir<%gep.b> = getelementptr ir<%b>, vp<%5>
+; CHECK-NEXT: vp<%7> = vector-pointer ir<%gep.b>
+; CHECK-NEXT: WIDEN ir<%load.b> = load vp<%7>
+; CHECK-NEXT: EXPRESSION vp<%8> = ir<%accum> + reduce.add (sub (0, mul (ir<%load.b> zext to i32), (ir<%load.a> zext to i32)))
+; CHECK-NEXT: EMIT vp<%index.next> = add nuw vp<%4>, vp<%1>
+; CHECK-NEXT: EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK-NEXT: No successors
+; CHECK-NEXT: }
+; CHECK-NEXT: Successor(s): middle.block
+; CHECK-EMPTY:
+; CHECK-NEXT: middle.block:
+; CHECK-NEXT: EMIT vp<%10> = compute-reduction-result ir<%accum>, vp<%8>
+; CHECK-NEXT: EMIT vp<%cmp.n> = icmp eq ir<1024>, vp<%2>
+; CHECK-NEXT: EMIT branch-on-cond vp<%cmp.n>
+; CHECK-NEXT: Successor(s): ir-bb<for.exit>, scalar.ph
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<for.exit>:
+; CHECK-NEXT: IR %add.lcssa = phi i32 [ %add, %for.body ] (extra operand: vp<%10> from middle.block)
+; CHECK-NEXT: No successors
+; CHECK-EMPTY:
+; CHECK-NEXT: scalar.ph:
+; CHECK-NEXT: EMIT-SCALAR vp<%bc.resume.val> = phi [ vp<%2>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%10>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: Successor(s): ir-bb<for.body>
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<for.body>:
+; CHECK-NEXT: IR %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ] (extra operand: vp<%bc.resume.val> from scalar.ph)
+; CHECK-NEXT: IR %accum = phi i32 [ 0, %entry ], [ %add, %for.body ] (extra operand: vp<%bc.merge.rdx> from scalar.ph)
+; CHECK-NEXT: IR %gep.a = getelementptr i8, ptr %a, i64 %iv
+; CHECK-NEXT: IR %load.a = load i8, ptr %gep.a, align 1
+; CHECK-NEXT: IR %ext.a = zext i8 %load.a to i32
+; CHECK-NEXT: IR %gep.b = getelementptr i8, ptr %b, i64 %iv
+; CHECK-NEXT: IR %load.b = load i8, ptr %gep.b, align 1
+; CHECK-NEXT: IR %ext.b = zext i8 %load.b to i32
+; CHECK-NEXT: IR %mul = mul i32 %ext.b, %ext.a
+; CHECK-NEXT: IR %add = sub i32 %accum, %mul
+; CHECK-NEXT: IR %iv.next = add i64 %iv, 1
+; CHECK-NEXT: IR %exitcond.not = icmp eq i64 %iv.next, 1024
+; CHECK-NEXT: No successors
+; CHECK-NEXT: }
+; CHECK: VPlan 'Final VPlan for VF={4},UF={1}' {
+; CHECK-NEXT: Live-in ir<4> = VF * UF
+; CHECK-NEXT: Live-in ir<1024> = vector-trip-count
+; CHECK-NEXT: Live-in ir<1024> = original trip-count
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<entry>:
+; CHECK-NEXT: Successor(s): ir-bb<scalar.ph>, ir-bb<vector.ph>
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<vector.ph>:
+; CHECK-NEXT: Successor(s): vector.body
+; CHECK-EMPTY:
+; CHECK-NEXT: vector.body:
+; CHECK-NEXT: EMIT-SCALAR vp<%index> = phi [ ir<0>, ir-bb<vector.ph> ], [ vp<%index.next>, vector.body ]
+; CHECK-NEXT: WIDEN-REDUCTION-PHI ir<%accum> = phi ir<0>, ir<%add>.1
+; CHECK-NEXT: CLONE ir<%gep.a> = getelementptr ir<%a>, vp<%index>
+; CHECK-NEXT: vp<%1> = vector-pointer ir<%gep.a>
+; CHECK-NEXT: WIDEN ir<%load.a> = load vp<%1>
+; CHECK-NEXT: CLONE ir<%gep.b> = getelementptr ir<%b>, vp<%index>
+; CHECK-NEXT: vp<%2> = vector-pointer ir<%gep.b>
+; CHECK-NEXT: WIDEN ir<%load.b> = load vp<%2>
+; CHECK-NEXT: WIDEN-CAST ir<%ext.b> = zext ir<%load.b> to i32
+; CHECK-NEXT: WIDEN-CAST ir<%ext.a> = zext ir<%load.a> to i32
+; CHECK-NEXT: WIDEN ir<%mul> = mul ir<%ext.b>, ir<%ext.a>
+; CHECK-NEXT: WIDEN ir<%add> = sub ir<0>, ir<%mul>
+; CHECK-NEXT: REDUCE ir<%add>.1 = ir<%accum> + reduce.add (ir<%add>)
+; CHECK-NEXT: EMIT vp<%index.next> = add nuw vp<%index>, ir<4>
+; CHECK-NEXT: EMIT branch-on-count vp<%index.next>, ir<1024>
+; CHECK-NEXT: Successor(s): middle.block, vector.body
+; CHECK-EMPTY:
+; CHECK-NEXT: middle.block:
+; CHECK-NEXT: EMIT vp<%4> = compute-reduction-result ir<%accum>, ir<%add>.1
+; CHECK-NEXT: EMIT vp<%cmp.n> = icmp eq ir<1024>, ir<1024>
+; CHECK-NEXT: EMIT branch-on-cond vp<%cmp.n>
+; CHECK-NEXT: Successor(s): ir-bb<for.exit>, ir-bb<scalar.ph>
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<for.exit>:
+; CHECK-NEXT: IR %add.lcssa = phi i32 [ %add, %for.body ] (extra operand: vp<%4> from middle.block)
+; CHECK-NEXT: No successors
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<scalar.ph>:
+; CHECK-NEXT: EMIT-SCALAR vp<%bc.resume.val> = phi [ ir<1024>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%4>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: Successor(s): ir-bb<for.body>
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<for.body>:
+; CHECK-NEXT: IR %iv = phi i64 [ 0, %scalar.ph ], [ %iv.next, %for.body ] (extra operand: vp<%bc.resume.val> from ir-bb<scalar.ph>)
+; CHECK-NEXT: IR %accum = phi i32 [ 0, %scalar.ph ], [ %add, %for.body ] (extra operand: vp<%bc.merge.rdx> from ir-bb<scalar.ph>)
+; CHECK-NEXT: IR %gep.a = getelementptr i8, ptr %a, i64 %iv
+; CHECK-NEXT: IR %load.a = load i8, ptr %gep.a, align 1
+; CHECK-NEXT: IR %ext.a = zext i8 %load.a to i32
+; CHECK-NEXT: IR %gep.b = getelementptr i8, ptr %b, i64 %iv
+; CHECK-NEXT: IR %load.b = load i8, ptr %gep.b, align 1
+; CHECK-NEXT: IR %ext.b = zext i8 %load.b to i32
+; CHECK-NEXT: IR %mul = mul i32 %ext.b, %ext.a
+; CHECK-NEXT: IR %add = sub i32 %accum, %mul
+; CHECK-NEXT: IR %iv.next = add i64 %iv, 1
+; CHECK-NEXT: IR %exitcond.not = icmp eq i64 %iv.next, 1024
+; CHECK-NEXT: No successors
+; CHECK-NEXT: }
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
----------------
fhahn wrote:
```suggestion
loop:
```
nit: consistency with other functions in file
https://github.com/llvm/llvm-project/pull/147255
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