[PATCH] D41227: [CGP] Fix Complex addressing mode for offset

[Serguei Katkov via Phabricator via llvm-commits]

skatkov created this revision.
skatkov added reviewers: john.brawn, reames.

If the offset is differ in two addressing mode we can continue only if
ScaleReg is not set due to we will use it as merge of different offsets.


https://reviews.llvm.org/D41227

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


Index: test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll
===================================================================
--- /dev/null
+++ test/Transforms/CodeGenPrepare/X86/sink-addrmode-select.ll
@@ -0,0 +1,19 @@
+; RUN: opt -S -codegenprepare -disable-complex-addr-modes=false -addr-sink-new-select=true  %s | FileCheck %s --check-prefix=CHECK
+target datalayout =
+"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Select when both offset and scale reg are present.
+define i64 @test1(i1 %c, i64* %b, i64 %scale) {
+; CHECK-LABEL: @test1
+entry:
+; CHECK-LABEL: entry:
+  %g = getelementptr inbounds i64, i64* %b, i64 %scale
+  %g1 = getelementptr inbounds i64, i64* %g, i64 8
+  %g2 = getelementptr inbounds i64, i64* %g, i64 16
+  %s = select i1 %c, i64* %g1, i64* %g2
+; CHECK-NOT: sunkaddr
+  %v = load i64 , i64* %s, align 8
+  ret i64 %v
+}
+
Index: lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- lib/CodeGen/CodeGenPrepare.cpp
+++ lib/CodeGen/CodeGenPrepare.cpp
@@ -2717,8 +2717,13 @@
     // 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.
+    // 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::ScaleField &&
+        (DifferentField != ExtAddrMode::BaseOffsField ||
+         !NewAddrMode.ScaledReg)) {
       AddrModes.emplace_back(NewAddrMode);
       return true;
     }


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