[PATCH] D80943: [X86] Add a flag to guard the wide load

[Guozhi Wei via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG587af86f1d8a: [X86] Add a flag to guard the wide load (authored by Carrot).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80943/new/

https://reviews.llvm.org/D80943

Files:
  llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
  llvm/lib/Target/X86/X86InstrInfo.td
  llvm/test/CodeGen/X86/no-wide-load.ll


Index: llvm/test/CodeGen/X86/no-wide-load.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/no-wide-load.ll
@@ -0,0 +1,22 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-- -x86-promote-anyext-load=false | FileCheck %s
+
+%struct.S = type { i32, i16, i16 }
+
+define void @foo(%struct.S* %p, i16 signext %s) {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movzwl 4(%rdi), %eax
+; CHECK-NEXT:    andl $-1121, %eax # imm = 0xFB9F
+; CHECK-NEXT:    orl $1024, %eax # imm = 0x400
+; CHECK-NEXT:    movw %ax, 4(%rdi)
+; CHECK-NEXT:    retq
+entry:
+  %f2 = getelementptr inbounds %struct.S, %struct.S* %p, i64 0, i32 1
+  %0 = load i16, i16* %f2, align 4
+  %1 = and i16 %0, -1121
+  %2 = or i16 %1, 1024
+  store i16 %2, i16* %f2, align 4
+  ret void
+}
+
Index: llvm/lib/Target/X86/X86InstrInfo.td
===================================================================
--- llvm/lib/Target/X86/X86InstrInfo.td
+++ llvm/lib/Target/X86/X86InstrInfo.td
@@ -1122,7 +1122,7 @@
   ISD::LoadExtType ExtType = LD->getExtensionType();
   if (ExtType == ISD::NON_EXTLOAD)
     return true;
-  if (ExtType == ISD::EXTLOAD)
+  if (ExtType == ISD::EXTLOAD && EnablePromoteAnyextLoad)
     return LD->getAlignment() >= 2 && LD->isSimple();
   return false;
 }]>;
@@ -1132,7 +1132,7 @@
   ISD::LoadExtType ExtType = LD->getExtensionType();
   if (ExtType == ISD::NON_EXTLOAD)
     return true;
-  if (ExtType == ISD::EXTLOAD)
+  if (ExtType == ISD::EXTLOAD && EnablePromoteAnyextLoad)
     return LD->getAlignment() >= 4 && LD->isSimple();
   return false;
 }]>;
Index: llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -40,6 +40,10 @@
     cl::desc("Enable setting constant bits to reduce size of mask immediates"),
     cl::Hidden);
 
+static cl::opt<bool> EnablePromoteAnyextLoad(
+    "x86-promote-anyext-load", cl::init(true),
+    cl::desc("Enable promoting aligned anyext load to wider load"), cl::Hidden);
+
 //===----------------------------------------------------------------------===//
 //                      Pattern Matcher Implementation
 //===----------------------------------------------------------------------===//


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