[PATCH] D41625: [DAGCombine] Fix for PR35765

[Sam Parker via Phabricator via llvm-commits]

samparker created this revision.
samparker added reviewers: dbabokin, craig.topper.

Remove the acceptance of ANY_EXTEND nodes while trying to move and nodes back to loads.

      

Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=35765


https://reviews.llvm.org/D41625

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/X86/pr35765.ll


Index: test/CodeGen/X86/pr35765.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/pr35765.ll
@@ -0,0 +1,42 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s
+
+ at ll = local_unnamed_addr global i64 0, align 8
+ at x = local_unnamed_addr global i64 2651237805702985558, align 8
+ at s1 = local_unnamed_addr global { i8, i8 } { i8 123, i8 5 }, align 2
+ at s2 = local_unnamed_addr global { i8, i8 } { i8 -122, i8 3 }, align 2
+
+; CHECK-LABEL: PR35765
+; CHECK: movzwl	s1(%rip), %ecx
+; CHECK: addl	$-1398, %ecx
+; CHECK: movl	$4, %eax
+; CHECK: shll	%cl, %eax
+; CHECK: movzwl	x(%rip), %ecx
+; CHECK: movzwl	s2(%rip), %edx
+; CHECK: notl	%edx
+; CHECK: orl	$63488, %edx
+; CHECK: movzwl	%dx, %edx
+; CHECK: orl	%ecx, %edx
+; CHECK: xorl	%eax, %edx
+; CHECK: movslq	%edx, %rax
+; CHECK: movq	%rax, ll(%rip)
+; CHECK: retq
+define void @PR35765() {
+entry:
+  %bf.load.i = load i16, i16* bitcast ({ i8, i8 }* @s1 to i16*), align 2
+  %bf.clear.i = and i16 %bf.load.i, 2047
+  %conv.i = zext i16 %bf.clear.i to i32
+  %sub.i = add nsw i32 %conv.i, -1398
+  %shl.i = shl i32 4, %sub.i
+  %0 = load i64, i64* @x, align 8
+  %bf.load1.i = load i16, i16* bitcast ({ i8, i8 }* @s2 to i16*), align 2
+  %bf.clear2.i = and i16 %bf.load1.i, 2047
+  %1 = xor i16 %bf.clear2.i, -1
+  %neg.i = zext i16 %1 to i64
+  %or.i = or i64 %0, %neg.i
+  %conv5.i = trunc i64 %or.i to i32
+  %conv6.i = and i32 %conv5.i, 65535
+  %xor.i = xor i32 %conv6.i, %shl.i
+  %conv7.i = sext i32 %xor.i to i64
+  store i64 %conv7.i, i64* @ll, align 8
+  ret void
+}
Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3850,7 +3850,6 @@
       return false;
     }
     case ISD::ZERO_EXTEND:
-    case ISD::ANY_EXTEND:
     case ISD::AssertZext: {
       unsigned ActiveBits = Mask->getAPIntValue().countTrailingOnes();
       EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits);


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