[PATCH] D99152: [AMX] Prototype for vector and amx bitcast.

[LuoYuanke via Phabricator via cfe-commits]

LuoYuanke added a comment.

> To be honest i don't really understand why `x86_amx` type is even there.
> It seems to me that if you just directly used `@llvm.x86.tileloadd64.internal` / `@llvm.x86.tilestored64.internal`,
> and `s/x86_amx/<256 x i32>/`, none of these problems would be here.

I explained in llvm-dev. I copy the content below.

Bitcasts is introduced by the frontend call amx intrinsics. We use vector to represent 2D amx tile in C language, on the other hand we don’t want to mix our amx tile to other vector operation, so x86_amx is introduced to isolate amx intrinsics from normal vector operation. The bitcast is to monitor that a normal vector is passed to amx intrinsics. In below example, we need to transform the bitcast to a vector store and an amx load intrinsic. The x86_amx* is unexpected at the beginning, but in the pass of InstrCombine the middle-end generate the x86_amx pointer.

define dso_local void @test_src_add(<256 x i32> %x, <256 x i32> %y, i16 %r, i16 %c, i8* %buf, i64 %s) {
; CHECK-LABEL: @test_src_add(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[TMP0:%.*]] = alloca <256 x i32>, align 64
; CHECK-NEXT:    [[ADD:%.*]] = add <256 x i32> [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT:    [[TMP1:%.*]] = bitcast <256 x i32>* [[TMP0]] to i8*
; CHECK-NEXT:    store <256 x i32> [[ADD]], <256 x i32>* [[TMP0]], align 1024
; CHECK-NEXT:    [[TMP2:%.*]] = call x86_amx @llvm.x86.tileloadd64.internal(i16 [[R:%.*]], i16 [[C:%.*]], i8* [[TMP1]], i64 64)
; CHECK-NEXT:    call void @llvm.x86.tilestored64.internal(i16 [[R]], i16 [[C]], i8* [[BUF:%.*]], i64 [[S:%.*]], x86_amx [[TMP2]])
; CHECK-NEXT:    ret void
;
entry:

  %add = add <256 x i32> %y, %x
  %t = bitcast <256 x i32> %add to x86_amx
  call void @llvm.x86.tilestored64.internal(i16 %r, i16 %c, i8* %buf, i64 %s, x86_amx %t)
  ret void

}


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D99152/new/

https://reviews.llvm.org/D99152