From 886e977c69c63868b0783041567362b3d2f8554a Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <asl@math.spbu.ru>
Date: Thu, 16 Jul 2009 14:24:16 +0000
Subject: [PATCH] Make FP zero to be legal FP immediate via LOAD ZERO

llvm-svn: 76034
---
 lib/Target/SystemZ/SystemZISelLowering.cpp |  5 +++
 lib/Target/SystemZ/SystemZInstrFP.td       | 43 ++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/lib/Target/SystemZ/SystemZISelLowering.cpp b/lib/Target/SystemZ/SystemZISelLowering.cpp
index 01ecf4fae90..4144f970d9b 100644
--- a/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -51,6 +51,11 @@ SystemZTargetLowering::SystemZTargetLowering(SystemZTargetMachine &tm) :
   if (!UseSoftFloat) {
     addRegisterClass(MVT::f32, SystemZ::FP32RegisterClass);
     addRegisterClass(MVT::f64, SystemZ::FP64RegisterClass);
+
+    addLegalFPImmediate(APFloat(+0.0));  // lzer
+    addLegalFPImmediate(APFloat(+0.0f)); // lzdr
+    addLegalFPImmediate(APFloat(-0.0));  // lzer + lner
+    addLegalFPImmediate(APFloat(-0.0f)); // lzdr + lndr
   }
 
   // Compute derived properties from the register classes
diff --git a/lib/Target/SystemZ/SystemZInstrFP.td b/lib/Target/SystemZ/SystemZInstrFP.td
index 202684f7bee..390104cf590 100644
--- a/lib/Target/SystemZ/SystemZInstrFP.td
+++ b/lib/Target/SystemZ/SystemZInstrFP.td
@@ -14,6 +14,17 @@
 
 // FIXME: multiclassify!
 
+//===----------------------------------------------------------------------===//
+// FP Pattern fragments
+
+def fpimm0 : PatLeaf<(fpimm), [{
+  return N->isExactlyValue(+0.0);
+}]>;
+
+def fpimmneg0 : PatLeaf<(fpimm), [{
+  return N->isExactlyValue(-0.0);
+}]>;
+
 let usesCustomDAGSchedInserter = 1 in {
   def SelectF32 : Pseudo<(outs FP32:$dst), (ins FP32:$src1, FP32:$src2, i8imm:$cc),
                         "# SelectF32 PSEUDO",
@@ -28,6 +39,16 @@ let usesCustomDAGSchedInserter = 1 in {
 //===----------------------------------------------------------------------===//
 // Move Instructions
 
+// Floating point constant loads.
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in {
+def LD_Fp032 : Pseudo<(outs FP32:$dst), (ins),
+                      "lzer\t{$dst}",
+                      [(set FP32:$dst, fpimm0)]>;
+def LD_Fp064 : Pseudo<(outs FP64:$dst), (ins),
+                      "lzdr\t{$dst}",
+                      [(set FP64:$dst, fpimm0)]>;
+}
+
 let neverHasSideEffects = 1 in {
 def FMOV32rr : Pseudo<(outs FP32:$dst), (ins FP32:$src),
                       "ler\t{$dst, $src}",
@@ -211,6 +232,20 @@ def FDIV64rm : Pseudo<(outs FP64:$dst), (ins FP64:$src1, rriaddr:$src2),
 
 } // isTwoAddress = 1
 
+def FSQRT32rr : Pseudo<(outs FP32:$dst), (ins FP32:$src),
+                       "sqebr\t{$dst, $src}",
+                       [(set FP32:$dst, (fsqrt FP32:$src))]>;
+def FSQRT64rr : Pseudo<(outs FP64:$dst), (ins FP64:$src),
+                       "sqdbr\t{$dst, $src}",
+                       [(set FP64:$dst, (fsqrt FP64:$src))]>;
+
+def FSQRT32rm : Pseudo<(outs FP32:$dst), (ins rriaddr:$src),
+                       "sqeb\t{$dst, $src}",
+                       [(set FP32:$dst, (fsqrt (load rriaddr:$src)))]>;
+def FSQRT64rm : Pseudo<(outs FP64:$dst), (ins rriaddr:$src),
+                       "sqdb\t{$dst, $src}",
+                       [(set FP64:$dst, (fsqrt (load rriaddr:$src)))]>;
+
 def FROUND64r32 : Pseudo<(outs FP32:$dst), (ins FP64:$src),
                          "ledbr\t{$dst, $src}",
                          [(set FP32:$dst, (fround FP64:$src))]>;
@@ -281,3 +316,11 @@ def FCMP64rm : Pseudo<(outs), (ins FP64:$src1, rriaddr:$src2),
                       [(SystemZcmp FP64:$src1, (load rriaddr:$src2)),
                        (implicit PSW)]>;
 } // Defs = [PSW]
+
+//===----------------------------------------------------------------------===//
+// Non-Instruction Patterns
+//===----------------------------------------------------------------------===//
+
+// Floating point constant -0.0
+def : Pat<(f32 fpimmneg0), (FNEG32rr (LD_Fp032))>;
+def : Pat<(f64 fpimmneg0), (FNEG64rr (LD_Fp064))>;