From: Nirav Dave <niravd@google.com>
Date: Thu, 24 Jan 2019 17:56:03 +0000 (+0000)
Subject: [SelectionDAGBuilder] Simplify HasSideEffect calculation. NFC.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a8d481282a769a572ad124335d26a32a713f3859;p=llvm

[SelectionDAGBuilder] Simplify HasSideEffect calculation. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352067 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 664cc3b9900..7244aacbf26 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -7505,9 +7505,9 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
   TargetLowering::AsmOperandInfoVector TargetConstraints = TLI.ParseConstraints(
       DAG.getDataLayout(), DAG.getSubtarget().getRegisterInfo(), CS);
 
-  bool hasMemory = false;
-
-  // Remember the HasSideEffect, AlignStack, AsmDialect, MayLoad and MayStore
+  // First Pass: Calculate HasSideEffects and ExtraFlags (AlignStack,
+  // AsmDialect, MayLoad, MayStore).
+  bool HasSideEffect = IA->hasSideEffects();
   ExtraFlags ExtraInfo(CS);
 
   unsigned ArgNo = 0;   // ArgNo - The argument of the CallInst.
@@ -7550,8 +7550,8 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
       OpInfo.ConstraintVT = MVT::Other;
     }
 
-    if (!hasMemory)
-      hasMemory = OpInfo.hasMemory(TLI);
+    if (!HasSideEffect)
+      HasSideEffect = OpInfo.hasMemory(TLI);
 
     // Determine if this InlineAsm MayLoad or MayStore based on the constraints.
     // FIXME: Could we compute this on OpInfo rather than T?
@@ -7562,14 +7562,9 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
     ExtraInfo.update(T);
   }
 
-  SDValue Chain, Flag;
-
   // We won't need to flush pending loads if this asm doesn't touch
   // memory and is nonvolatile.
-  if (hasMemory || IA->hasSideEffects())
-    Chain = getRoot();
-  else
-    Chain = DAG.getRoot();
+  SDValue Flag, Chain = (HasSideEffect) ? getRoot() : DAG.getRoot();
 
   // Second pass over the constraints: compute which constraint option to use.
   for (SDISelAsmOperandInfo &OpInfo : ConstraintOperands) {
@@ -7925,8 +7920,7 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
     Chain = DAG.getNode(ISD::TokenFactor, getCurSDLoc(), MVT::Other, OutChains);
 
   // Only Update Root if inline assembly has a memory effect.
-  if (ResultValues.empty() || IA->hasSideEffects() || hasMemory ||
-      !OutChains.empty())
+  if (ResultValues.empty() || HasSideEffect || !OutChains.empty())
     DAG.setRoot(Chain);
 }