[llvm] [docs][NVPTX] Use opaque pointers in IR examples (NFC) (PR #81941)
Youngsuk Kim via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 15 15:55:21 PST 2024
https://github.com/JOE1994 created https://github.com/llvm/llvm-project/pull/81941
Replace outdated typed-pointer notation in LLVM IR examples. NFC.
>From acfe56e9f659556b13602a6e36ae7448cb0b954d Mon Sep 17 00:00:00 2001
From: Youngsuk Kim <youngsuk.kim at hpe.com>
Date: Thu, 15 Feb 2024 17:31:52 -0600
Subject: [PATCH] [docs][NVPTX] Use opaque pointers in IR examples (NFC)
Replace outdated typed-pointer notation in LLVM IR examples. NFC.
---
llvm/docs/NVPTXUsage.rst | 72 ++++++++++++++++++----------------------
1 file changed, 33 insertions(+), 39 deletions(-)
diff --git a/llvm/docs/NVPTXUsage.rst b/llvm/docs/NVPTXUsage.rst
index 6a55b1205a7618..4385cba3ada0d6 100644
--- a/llvm/docs/NVPTXUsage.rst
+++ b/llvm/docs/NVPTXUsage.rst
@@ -53,15 +53,15 @@ function ``@my_kernel`` is callable from host code, but ``@my_fmad`` is not.
ret float %add
}
- define void @my_kernel(float* %ptr) {
- %val = load float, float* %ptr
+ define void @my_kernel(ptr %ptr) {
+ %val = load float, ptr %ptr
%ret = call float @my_fmad(float %val, float %val, float %val)
- store float %ret, float* %ptr
+ store float %ret, ptr %ptr
ret void
}
!nvvm.annotations = !{!1}
- !1 = !{void (float*)* @my_kernel, !"kernel", i32 1}
+ !1 = !{ptr @my_kernel, !"kernel", i32 1}
When compiled, the PTX kernel functions are callable by host-side code.
@@ -140,10 +140,10 @@ These are overloaded intrinsics. You can use these on any pointer types.
.. code-block:: llvm
- declare i8* @llvm.nvvm.ptr.global.to.gen.p0i8.p1i8(i8 addrspace(1)*)
- declare i8* @llvm.nvvm.ptr.shared.to.gen.p0i8.p3i8(i8 addrspace(3)*)
- declare i8* @llvm.nvvm.ptr.constant.to.gen.p0i8.p4i8(i8 addrspace(4)*)
- declare i8* @llvm.nvvm.ptr.local.to.gen.p0i8.p5i8(i8 addrspace(5)*)
+ declare ptr @llvm.nvvm.ptr.global.to.gen.p0.p1(ptr addrspace(1))
+ declare ptr @llvm.nvvm.ptr.shared.to.gen.p0.p3(ptr addrspace(3))
+ declare ptr @llvm.nvvm.ptr.constant.to.gen.p0.p4(ptr addrspace(4))
+ declare ptr @llvm.nvvm.ptr.local.to.gen.p0.p5(ptr addrspace(5))
Overview:
"""""""""
@@ -168,10 +168,10 @@ These are overloaded intrinsics. You can use these on any pointer types.
.. code-block:: llvm
- declare i8 addrspace(1)* @llvm.nvvm.ptr.gen.to.global.p1i8.p0i8(i8*)
- declare i8 addrspace(3)* @llvm.nvvm.ptr.gen.to.shared.p3i8.p0i8(i8*)
- declare i8 addrspace(4)* @llvm.nvvm.ptr.gen.to.constant.p4i8.p0i8(i8*)
- declare i8 addrspace(5)* @llvm.nvvm.ptr.gen.to.local.p5i8.p0i8(i8*)
+ declare ptr addrspace(1) @llvm.nvvm.ptr.gen.to.global.p1.p0(ptr)
+ declare ptr addrspace(3) @llvm.nvvm.ptr.gen.to.shared.p3.p0(ptr)
+ declare ptr addrspace(4) @llvm.nvvm.ptr.gen.to.constant.p4.p0(ptr)
+ declare ptr addrspace(5) @llvm.nvvm.ptr.gen.to.local.p5.p0(ptr)
Overview:
"""""""""
@@ -436,35 +436,33 @@ The Kernel
; Intrinsic to read X component of thread ID
declare i32 @llvm.nvvm.read.ptx.sreg.tid.x() readnone nounwind
- define void @kernel(float addrspace(1)* %A,
- float addrspace(1)* %B,
- float addrspace(1)* %C) {
+ define void @kernel(ptr addrspace(1) %A,
+ ptr addrspace(1) %B,
+ ptr addrspace(1) %C) {
entry:
; What is my ID?
%id = tail call i32 @llvm.nvvm.read.ptx.sreg.tid.x() readnone nounwind
; Compute pointers into A, B, and C
- %ptrA = getelementptr float, float addrspace(1)* %A, i32 %id
- %ptrB = getelementptr float, float addrspace(1)* %B, i32 %id
- %ptrC = getelementptr float, float addrspace(1)* %C, i32 %id
+ %ptrA = getelementptr float, ptr addrspace(1) %A, i32 %id
+ %ptrB = getelementptr float, ptr addrspace(1) %B, i32 %id
+ %ptrC = getelementptr float, ptr addrspace(1) %C, i32 %id
; Read A, B
- %valA = load float, float addrspace(1)* %ptrA, align 4
- %valB = load float, float addrspace(1)* %ptrB, align 4
+ %valA = load float, ptr addrspace(1) %ptrA, align 4
+ %valB = load float, ptr addrspace(1) %ptrB, align 4
; Compute C = A + B
%valC = fadd float %valA, %valB
; Store back to C
- store float %valC, float addrspace(1)* %ptrC, align 4
+ store float %valC, ptr addrspace(1) %ptrC, align 4
ret void
}
!nvvm.annotations = !{!0}
- !0 = !{void (float addrspace(1)*,
- float addrspace(1)*,
- float addrspace(1)*)* @kernel, !"kernel", i32 1}
+ !0 = !{ptr @kernel, !"kernel", i32 1}
We can use the LLVM ``llc`` tool to directly run the NVPTX code generator:
@@ -613,9 +611,7 @@ For the previous example, we have:
.. code-block:: llvm
!nvvm.annotations = !{!0}
- !0 = !{void (float addrspace(1)*,
- float addrspace(1)*,
- float addrspace(1)*)* @kernel, !"kernel", i32 1}
+ !0 = !{ptr @kernel, !"kernel", i32 1}
Here, we have a single metadata declaration in ``nvvm.annotations``. This
metadata annotates our ``@kernel`` function with the ``kernel`` attribute.
@@ -820,35 +816,33 @@ Libdevice provides an ``__nv_powf`` function that we will use.
; libdevice function
declare float @__nv_powf(float, float)
- define void @kernel(float addrspace(1)* %A,
- float addrspace(1)* %B,
- float addrspace(1)* %C) {
+ define void @kernel(ptr addrspace(1) %A,
+ ptr addrspace(1) %B,
+ ptr addrspace(1) %C) {
entry:
; What is my ID?
%id = tail call i32 @llvm.nvvm.read.ptx.sreg.tid.x() readnone nounwind
; Compute pointers into A, B, and C
- %ptrA = getelementptr float, float addrspace(1)* %A, i32 %id
- %ptrB = getelementptr float, float addrspace(1)* %B, i32 %id
- %ptrC = getelementptr float, float addrspace(1)* %C, i32 %id
+ %ptrA = getelementptr float, ptr addrspace(1) %A, i32 %id
+ %ptrB = getelementptr float, ptr addrspace(1) %B, i32 %id
+ %ptrC = getelementptr float, ptr addrspace(1) %C, i32 %id
; Read A, B
- %valA = load float, float addrspace(1)* %ptrA, align 4
- %valB = load float, float addrspace(1)* %ptrB, align 4
+ %valA = load float, ptr addrspace(1) %ptrA, align 4
+ %valB = load float, ptr addrspace(1) %ptrB, align 4
; Compute C = pow(A, B)
%valC = call float @__nv_powf(float %valA, float %valB)
; Store back to C
- store float %valC, float addrspace(1)* %ptrC, align 4
+ store float %valC, ptr addrspace(1) %ptrC, align 4
ret void
}
!nvvm.annotations = !{!0}
- !0 = !{void (float addrspace(1)*,
- float addrspace(1)*,
- float addrspace(1)*)* @kernel, !"kernel", i32 1}
+ !0 = !{ptr @kernel, !"kernel", i32 1}
To compile this kernel, we perform the following steps:
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