[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset #88493

fengfeng09 · 2024-04-12T10:03:06Z

Or-disjoint application.

github-actions · 2024-04-12T10:03:29Z

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llvmbot · 2024-04-12T10:04:22Z

@llvm/pr-subscribers-llvm-selectiondag

Author: fengfeng (fengfeng09)

Changes

Or-disjoint application.

Full diff: https://github.com/llvm/llvm-project/pull/88493.diff

2 Files Affected:

(modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (+3)
(added) llvm/test/CodeGen/AVR/base-with-add-like-constant-offset.ll (+20)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 1dd0fa49a460f8..67feb47fef076f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5191,6 +5191,9 @@ bool SelectionDAG::isADDLike(SDValue Op) const {
 }
 
 bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {
+  if (isADDLike(Op) && isa<ConstantSDNode>(Op.getOperand(1)))
+    return true;
+
   if ((Op.getOpcode() != ISD::ADD && Op.getOpcode() != ISD::OR) ||
       !isa<ConstantSDNode>(Op.getOperand(1)))
     return false;
diff --git a/llvm/test/CodeGen/AVR/base-with-add-like-constant-offset.ll b/llvm/test/CodeGen/AVR/base-with-add-like-constant-offset.ll
new file mode 100644
index 00000000000000..6077f71b5efe06
--- /dev/null
+++ b/llvm/test/CodeGen/AVR/base-with-add-like-constant-offset.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc -mtriple=avr %s -start-before=avr-isel -o - -stop-after=avr-isel | FileCheck %s
+
+define void @test(i16 %x, ptr addrspace(1) %o) {
+  ; CHECK-LABEL: name: test
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK-NEXT:   liveins: $r25r24, $r23r22
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:dregs = COPY $r23r22
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:dregs = COPY $r25r24
+  ; CHECK-NEXT:   [[COPY2:%[0-9]+]]:ptrdispregs = COPY [[COPY]]
+  ; CHECK-NEXT:   STDWPtrQRr [[COPY2]], 10, [[COPY1]] :: (store (s16) into %ir.addr, align 1, addrspace 1)
+  ; CHECK-NEXT:   RET implicit $r1
+  %int = ptrtoint ptr addrspace(1) %o to i16
+  %or = or disjoint i16 %int, 10
+  %addr = inttoptr i16 %or to ptr addrspace(1)
+  store i16 %x, ptr addrspace(1) %addr
+  ret void
+}
+

RKSimon · 2024-04-12T11:18:12Z

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -5191,6 +5191,9 @@ bool SelectionDAG::isADDLike(SDValue Op) const {
 }

 bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {


Can we not just simplify this function to:

bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const { return (Op.getOpcode() == ISD::ADD || isADDLike(Op)) && isa<ConstantSDNode>(Op.getOperand(1)); }

Good suggestion.

RKSimon

LGTM

arsenm

Title should be improved, it is missing any context

topperc · 2024-04-12T23:18:36Z

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

-    return false;
-
-  return true;
+  return (Op.getOpcode() == ISD::ADD || isADDLike(Op)) &&


This can call computeKnownBits on both operands an OR that doesn't have a constant right hand side. Is there better way to do that with the cheap constant right hand side check first?

nikic · 2024-04-13T02:36:31Z

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

-    return false;
-
-  return true;
+  return isa<ConstantSDNode>(Op.getOperand(1)) &&


This will crash if the node doesn't have a second operand.

nikic

LG

Signed-off-by: feng.feng <feng.feng@iluvatar.com>

If the addr base of a Load/Store Inst is an Or-disjoint with a constant, it could be selected to an MI with constans offset if the target have. Signed-off-by: feng.feng <feng.feng@iluvatar.com>

fengfeng09 · 2024-04-15T04:30:47Z

I have no write access to the repo，could someone help me to merge this PR？

github-actions · 2024-04-15T05:00:04Z

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…lvm#88493) Signed-off-by: feng.feng <feng.feng@iluvatar.com>

llvmbot added the llvm:SelectionDAG SelectionDAGISel as well label Apr 12, 2024

RKSimon reviewed Apr 12, 2024

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RKSimon requested review from arsenm, nikic and topperc April 12, 2024 11:18

fengfeng09 force-pushed the base-with-add-like-constant-offset branch from fa99586 to f20ac0a Compare April 12, 2024 15:19

fengfeng09 requested a review from RKSimon April 12, 2024 15:20

RKSimon approved these changes Apr 12, 2024

View reviewed changes

arsenm reviewed Apr 12, 2024

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topperc reviewed Apr 12, 2024

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fengfeng09 force-pushed the base-with-add-like-constant-offset branch from f20ac0a to 88d114e Compare April 13, 2024 01:56

fengfeng09 changed the title ~~Base with add like constant offset~~ Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset Apr 13, 2024

fengfeng09 requested review from topperc, arsenm and RKSimon April 13, 2024 02:00

nikic reviewed Apr 13, 2024

View reviewed changes

fengfeng09 force-pushed the base-with-add-like-constant-offset branch 2 times, most recently from b1fafcc to 51c05ea Compare April 13, 2024 09:11

fengfeng09 requested a review from nikic April 13, 2024 09:21

nikic approved these changes Apr 13, 2024

View reviewed changes

nikic changed the title ~~Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset~~ [SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset Apr 13, 2024

fengfeng09 added 2 commits April 15, 2024 12:29

Precommit test for refine isBaseWithConstantOffset. NFC

f3b5ac7

Signed-off-by: feng.feng <feng.feng@iluvatar.com>

[SelectionDAG] Disjoint Or could be also constant offset.

8e03689

If the addr base of a Load/Store Inst is an Or-disjoint with a constant, it could be selected to an MI with constans offset if the target have. Signed-off-by: feng.feng <feng.feng@iluvatar.com>

fengfeng09 force-pushed the base-with-add-like-constant-offset branch from 51c05ea to 8e03689 Compare April 15, 2024 04:29

nikic merged commit 7177dc2 into llvm:main Apr 15, 2024
3 of 4 checks passed

fengfeng09 deleted the base-with-add-like-constant-offset branch April 15, 2024 05:18

bazuzi pushed a commit to bazuzi/llvm-project that referenced this pull request Apr 15, 2024

[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset (l…

3d08b60

…lvm#88493) Signed-off-by: feng.feng <feng.feng@iluvatar.com>

aniplcc pushed a commit to aniplcc/llvm-project that referenced this pull request Apr 15, 2024

[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset (l…

8217870

…lvm#88493) Signed-off-by: feng.feng <feng.feng@iluvatar.com>

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[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset #88493

[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset #88493

fengfeng09 commented Apr 12, 2024

github-actions bot commented Apr 12, 2024

llvmbot commented Apr 12, 2024

RKSimon Apr 12, 2024

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fengfeng09 commented Apr 15, 2024

github-actions bot commented Apr 15, 2024

		@@ -5191,6 +5191,9 @@ bool SelectionDAG::isADDLike(SDValue Op) const {
		}

		bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {

[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset #88493

[SDAG] Apply or-disjoint in SelectionDAG::isBaseWithConstantOffset #88493

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