[llvm-branch-commits] [llvm] a3532c5 - [SVE] Don't use LocalStackAllocation for SVE objects
Hans Wennborg via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Fri Jul 31 08:35:55 PDT 2020
Author: David Sherwood
Date: 2020-07-31T17:27:49+02:00
New Revision: a3532c58be5c3a4107549c2462613be76507fe55
URL: https://github.com/llvm/llvm-project/commit/a3532c58be5c3a4107549c2462613be76507fe55
DIFF: https://github.com/llvm/llvm-project/commit/a3532c58be5c3a4107549c2462613be76507fe55.diff
LOG: [SVE] Don't use LocalStackAllocation for SVE objects
I have introduced a new TargetFrameLowering query function:
isStackIdSafeForLocalArea
that queries whether or not it is safe for objects of a given stack
id to be bundled into the local area. The default behaviour is to
always bundle regardless of the stack id, however for AArch64 this is
overriden so that it's only safe for fixed-size stack objects.
There is future work here to extend this algorithm for multiple local
areas so that SVE stack objects can be bundled together and accessed
from their own virtual base-pointer.
Differential Revision: https://reviews.llvm.org/D83859
(cherry picked from commit 14bc85e0ebb6c00c1672158ab6a692bfbb11e1cc)
Added:
llvm/test/CodeGen/AArch64/sve-localstackalloc.mir
Modified:
llvm/include/llvm/CodeGen/TargetFrameLowering.h
llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
llvm/lib/Target/AArch64/AArch64FrameLowering.h
Removed:
################################################################################
diff --git a/llvm/include/llvm/CodeGen/TargetFrameLowering.h b/llvm/include/llvm/CodeGen/TargetFrameLowering.h
index c3a11b199675..d6580430daf7 100644
--- a/llvm/include/llvm/CodeGen/TargetFrameLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetFrameLowering.h
@@ -134,6 +134,12 @@ class TargetFrameLowering {
/// was called).
virtual unsigned getStackAlignmentSkew(const MachineFunction &MF) const;
+ /// This method returns whether or not it is safe for an object with the
+ /// given stack id to be bundled into the local area.
+ virtual bool isStackIdSafeForLocalArea(unsigned StackId) const {
+ return true;
+ }
+
/// getOffsetOfLocalArea - This method returns the offset of the local area
/// from the stack pointer on entrance to a function.
///
diff --git a/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp b/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
index 6c5ef0255a08..204fb556d810 100644
--- a/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
+++ b/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
@@ -220,6 +220,8 @@ void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
continue;
if (StackProtectorFI == (int)i)
continue;
+ if (!TFI.isStackIdSafeForLocalArea(MFI.getStackID(i)))
+ continue;
switch (MFI.getObjectSSPLayout(i)) {
case MachineFrameInfo::SSPLK_None:
@@ -254,6 +256,8 @@ void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
continue;
if (ProtectedObjs.count(i))
continue;
+ if (!TFI.isStackIdSafeForLocalArea(MFI.getStackID(i)))
+ continue;
AdjustStackOffset(MFI, i, Offset, StackGrowsDown, MaxAlign);
}
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.h b/llvm/lib/Target/AArch64/AArch64FrameLowering.h
index 9d0a6d9eaf25..444740cb50ab 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.h
@@ -105,6 +105,12 @@ class AArch64FrameLowering : public TargetFrameLowering {
}
}
+ bool isStackIdSafeForLocalArea(unsigned StackId) const override {
+ // We don't support putting SVE objects into the pre-allocated local
+ // frame block at the moment.
+ return StackId != TargetStackID::SVEVector;
+ }
+
private:
bool shouldCombineCSRLocalStackBump(MachineFunction &MF,
uint64_t StackBumpBytes) const;
diff --git a/llvm/test/CodeGen/AArch64/sve-localstackalloc.mir b/llvm/test/CodeGen/AArch64/sve-localstackalloc.mir
new file mode 100644
index 000000000000..c20846c54b6a
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/sve-localstackalloc.mir
@@ -0,0 +1,61 @@
+# RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve -run-pass=localstackalloc -o - %s | FileCheck %s
+
+--- |
+ ; ModuleID = '<stdin>'
+ source_filename = "<stdin>"
+ target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+ target triple = "aarch64-unknown-linux-gnu"
+
+ define <vscale x 32 x i8> @insert_32i8_idx(<vscale x 32 x i8> %a, i8 %elt, i64 %idx) #0 {
+ %ins = insertelement <vscale x 32 x i8> %a, i8 %elt, i64 %idx
+ ret <vscale x 32 x i8> %ins
+ }
+
+ attributes #0 = { "target-features"="+sve" }
+
+...
+---
+name: insert_32i8_idx
+alignment: 4
+tracksRegLiveness: true
+registers:
+ - { id: 0, class: zpr, preferred-register: '' }
+ - { id: 1, class: zpr, preferred-register: '' }
+ - { id: 2, class: gpr32, preferred-register: '' }
+ - { id: 3, class: gpr64, preferred-register: '' }
+ - { id: 5, class: ppr_3b, preferred-register: '' }
+ - { id: 6, class: gpr64sp, preferred-register: '' }
+ - { id: 7, class: zpr, preferred-register: '' }
+ - { id: 8, class: zpr, preferred-register: '' }
+liveins:
+ - { reg: '$z0', virtual-reg: '%0' }
+ - { reg: '$z1', virtual-reg: '%1' }
+ - { reg: '$w0', virtual-reg: '%2' }
+frameInfo:
+ maxAlignment: 1
+ maxCallFrameSize: 0
+# CHECK-LABEL: name: insert_32i8_idx
+# CHECK: localFrameSize: 0
+stack:
+ - { id: 0, name: '', type: default, offset: 0, size: 32, alignment: 16,
+ stack-id: sve-vec, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+machineFunctionInfo: {}
+body: |
+ bb.0 (%ir-block.0):
+ liveins: $z0, $z1, $w0
+
+ %2:gpr32 = COPY $w0
+ %1:zpr = COPY $z1
+ %0:zpr = COPY $z0
+ %5:ppr_3b = PTRUE_B 31
+ %6:gpr64sp = ADDXri %stack.0, 0, 0
+ ST1B_IMM %1, %5, %6, 1 :: (store unknown-size, align 16)
+ ST1B_IMM %0, %5, %stack.0, 0 :: (store unknown-size into %stack.0, align 16)
+ %7:zpr = LD1B_IMM %5, %6, 1 :: (load unknown-size from %stack.0 + 16, align 16)
+ %8:zpr = LD1B_IMM %5, %stack.0, 0 :: (load unknown-size from %stack.0, align 16)
+ $z0 = COPY %8
+ $z1 = COPY %7
+ RET_ReallyLR implicit $z0, implicit $z1
+
+...
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