[llvm] r192721 - Fix PR16807

[Michael Liao]

Author: hliao
Date: Tue Oct 15 12:51:02 2013
New Revision: 192721

URL: http://llvm.org/viewvc/llvm-project?rev=192721&view=rev
Log:
Fix PR16807

- Lower signed division by constant powers-of-2 to target-independent
  DAG operators instead of target-dependent ones to support them better
  on targets where vector types are legal but shift operators on that
  types are illegal. E.g., on AVX, PSRAW is only available on <8 x i16>
  though <16 x i16> is a legal type.


Added:
    llvm/trunk/test/CodeGen/X86/pr16807.ll
Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=192721&r1=192720&r2=192721&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Oct 15 12:51:02 2013
@@ -12467,14 +12467,24 @@ static SDValue LowerSDIV(SDValue Op, Sel
       (SplatValue.isPowerOf2() || (-SplatValue).isPowerOf2())) {
     unsigned lg2 = SplatValue.countTrailingZeros();
     // Splat the sign bit.
-    SDValue Sz = DAG.getConstant(EltTy.getSizeInBits()-1, MVT::i32);
-    SDValue SGN = getTargetVShiftNode(X86ISD::VSRAI, dl, VT, N0, Sz, DAG);
+    SmallVector<SDValue, 16> Sz(NumElts,
+                                DAG.getConstant(EltTy.getSizeInBits() - 1,
+                                                EltTy));
+    SDValue SGN = DAG.getNode(ISD::SRA, dl, VT, N0,
+                              DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Sz[0],
+                                          NumElts));
     // Add (N0 < 0) ? abs2 - 1 : 0;
-    SDValue Amt = DAG.getConstant(EltTy.getSizeInBits() - lg2, MVT::i32);
-    SDValue SRL = getTargetVShiftNode(X86ISD::VSRLI, dl, VT, SGN, Amt, DAG);
+    SmallVector<SDValue, 16> Amt(NumElts,
+                                 DAG.getConstant(EltTy.getSizeInBits() - lg2,
+                                                 EltTy));
+    SDValue SRL = DAG.getNode(ISD::SRL, dl, VT, SGN,
+                              DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Amt[0],
+                                          NumElts));
     SDValue ADD = DAG.getNode(ISD::ADD, dl, VT, N0, SRL);
-    SDValue Lg2Amt = DAG.getConstant(lg2, MVT::i32);
-    SDValue SRA = getTargetVShiftNode(X86ISD::VSRAI, dl, VT, ADD, Lg2Amt, DAG);
+    SmallVector<SDValue, 16> Lg2Amt(NumElts, DAG.getConstant(lg2, EltTy));
+    SDValue SRA = DAG.getNode(ISD::SRA, dl, VT, ADD,
+                              DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Lg2Amt[0],
+                                          NumElts));
 
     // If we're dividing by a positive value, we're done.  Otherwise, we must
     // negate the result.

Added: llvm/trunk/test/CodeGen/X86/pr16807.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr16807.ll?rev=192721&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr16807.ll (added)
+++ llvm/trunk/test/CodeGen/X86/pr16807.ll Tue Oct 15 12:51:02 2013
@@ -0,0 +1,18 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnu -mcpu=core-avx-i | FileCheck %s
+
+define <16 x i16> @f_fu(<16 x i16> %bf) {
+allocas:
+  %avg.i.i = sdiv <16 x i16> %bf, <i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4, i16 4>
+  ret <16 x i16> %avg.i.i
+}
+
+; CHECK: f_fu
+; CHECK: psraw
+; CHECK: psrlw
+; CHECK: paddw
+; CHECK: psraw
+; CHECK: psraw
+; CHECK: psrlw
+; CHECK: paddw
+; CHECK: psraw
+; CHECK: ret