[PATCH] D42230: [CGP] Fix the GV handling in complex addressing mode

[Serguei Katkov via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL323192: [CGP] Fix the GV handling in complex addressing mode (authored by skatkov, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D42230?vs=130828&id=131040#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D42230

Files:
  llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
  llvm/trunk/test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll


Index: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
+++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
@@ -2694,26 +2694,32 @@
     else if (DifferentField != ThisDifferentField)
       DifferentField = ExtAddrMode::MultipleFields;
 
-    // If NewAddrMode differs in only one dimension, and that dimension isn't
-    // the amount that ScaledReg is scaled by, then we can handle it by
-    // inserting a phi/select later on. Even if NewAddMode is the same
-    // we still need to collect it due to original value is different.
-    // And later we will need all original values as anchors during
-    // finding the common Phi node.
+    // If NewAddrMode differs in more than one dimension we cannot handle it.
+    bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;
+
+    // If Scale Field is different then we reject.
+    CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;
+
     // We also must reject the case when base offset is different and
     // scale reg is not null, we cannot handle this case due to merge of
     // different offsets will be used as ScaleReg.
-    if (DifferentField != ExtAddrMode::MultipleFields &&
-        DifferentField != ExtAddrMode::ScaleField &&
-        (DifferentField != ExtAddrMode::BaseOffsField ||
-         !NewAddrMode.ScaledReg)) {
+    CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
+                              !NewAddrMode.ScaledReg);
+
+    // We also must reject the case when GV is different and BaseReg installed
+    // due to we want to use base reg as a merge of GV values.
+    CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
+                              !NewAddrMode.HasBaseReg);
+
+    // Even if NewAddMode is the same we still need to collect it due to
+    // original value is different. And later we will need all original values
+    // as anchors during finding the common Phi node.
+    if (CanHandle)
       AddrModes.emplace_back(NewAddrMode);
-      return true;
-    }
+    else
+      AddrModes.clear();
 
-    // We couldn't combine NewAddrMode with the rest, so return failure.
-    AddrModes.clear();
-    return false;
+    return CanHandle;
   }
 
   /// \brief Combine the addressing modes we've collected into a single
Index: llvm/trunk/test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll
===================================================================
--- llvm/trunk/test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll
+++ llvm/trunk/test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll
@@ -17,3 +17,18 @@
   ret i64 %v
 }
 
+ at gv1 = external global i8, align 16
+ at gv2 = external global i8, align 16
+
+; Select when both GV and base reg are present.
+define i8 @test2(i1 %c, i64 %b) {
+; CHECK-LABEL: @test2
+entry:
+; CHECK-LABEL: entry:
+  %g1 = getelementptr inbounds i8, i8* @gv1, i64 %b
+  %g2 = getelementptr inbounds i8, i8* @gv2, i64 %b
+  %s = select i1 %c, i8* %g1, i8* %g2
+; CHECK-NOT: sunkaddr
+  %v = load i8 , i8* %s, align 8
+  ret i8 %v
+}


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