From: Michael Kuperstein <michael.m.kuperstein@intel.com>
Date: Mon, 10 Nov 2014 20:40:21 +0000 (+0000)
Subject: [X86] Fix pattern match for 32-to-64-bit zext in the presence of AssertSext
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1a66dc74684ddd1f536be10e1afde4f3cec68396;p=oota-llvm.git

[X86] Fix pattern match for 32-to-64-bit zext in the presence of AssertSext

This fixes an issue with matching trunc -> assertsext -> zext on x86-64, which would not zero the high 32-bits.
See PR20494 for details.

Differential Revision: http://reviews.llvm.org/D6128

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221626 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86InstrCompiler.td b/lib/Target/X86/X86InstrCompiler.td
index bf25672b2f6..117b6ff2103 100644
--- a/lib/Target/X86/X86InstrCompiler.td
+++ b/lib/Target/X86/X86InstrCompiler.td
@@ -1191,6 +1191,7 @@ def def32 : PatLeaf<(i32 GR32:$src), [{
   return N->getOpcode() != ISD::TRUNCATE &&
          N->getOpcode() != TargetOpcode::EXTRACT_SUBREG &&
          N->getOpcode() != ISD::CopyFromReg &&
+         N->getOpcode() != ISD::AssertSext &&
          N->getOpcode() != X86ISD::CMOV;
 }]>;
 
diff --git a/test/CodeGen/X86/TruncAssertZext.ll b/test/CodeGen/X86/TruncAssertZext.ll
new file mode 100644
index 00000000000..08079e98f2d
--- /dev/null
+++ b/test/CodeGen/X86/TruncAssertZext.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s -O2 -march=x86-64 | FileCheck %s
+; Checks that a zeroing mov is inserted for the trunc/zext pair even when
+; the source of the zext is an AssertSext node
+; PR20494
+
+define i64 @main(i64 %a) { 
+; CHECK-LABEL: main
+; CHECK: movl %ecx, %eax
+; CHECK: ret
+  %or = or i64 %a, -2
+  %trunc = trunc i64 %or to i32
+  br label %l
+l:
+  %ext = zext i32 %trunc to i64
+  ret i64 %ext
+}