[SystemZ] Use LOAD AND TEST for comparisons with -0

...since it os equivalent to comparison with +0.

llvm-svn: 196580

2 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZInstrFP.td b/llvm/lib/Target/SystemZ/SystemZInstrFP.td
index 60800460fca..07f253d8cdc 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrFP.td
+++ b/llvm/lib/Target/SystemZ/SystemZInstrFP.td
@@ -46,9 +46,9 @@ let Defs = [CC], CCValues = 0xF, CompareZeroCCMask = 0xF in {
   defm LTDBR : LoadAndTestRRE<"ltdb", 0xB312, FP64>;
   defm LTXBR : LoadAndTestRRE<"ltxb", 0xB342, FP128>;
 }
-def : CompareZeroFP<LTEBRCompare, FP32>;
-def : CompareZeroFP<LTDBRCompare, FP64>;
-def : CompareZeroFP<LTXBRCompare, FP128>;
+defm : CompareZeroFP<LTEBRCompare, FP32>;
+defm : CompareZeroFP<LTDBRCompare, FP64>;
+defm : CompareZeroFP<LTXBRCompare, FP128>;
 
 // Moves between 64-bit integer and floating-point registers.
 def LGDR : UnaryRRE<"lgd", 0xB3CD, bitconvert, GR64, FP64>;
diff --git a/llvm/lib/Target/SystemZ/SystemZPatterns.td b/llvm/lib/Target/SystemZ/SystemZPatterns.td
index 7706351e54b..c0f94ecbe2c 100644
--- a/llvm/lib/Target/SystemZ/SystemZPatterns.td
+++ b/llvm/lib/Target/SystemZ/SystemZPatterns.td
@@ -148,5 +148,8 @@ multiclass BlockLoadStore<SDPatternOperator load, ValueType vt,
 // Record that INSN is a LOAD AND TEST that can be used to compare
 // registers in CLS against zero.  The instruction has separate R1 and R2
 // operands, but they must be the same when the instruction is used like this.
-class CompareZeroFP<Instruction insn, RegisterOperand cls>
-  : Pat<(z_fcmp cls:$reg, (fpimm0)), (insn cls:$reg, cls:$reg)>;
+multiclass CompareZeroFP<Instruction insn, RegisterOperand cls> {
+  def : Pat<(z_fcmp cls:$reg, (fpimm0)), (insn cls:$reg, cls:$reg)>;
+  // The sign of the zero makes no difference.
+  def : Pat<(z_fcmp cls:$reg, (fpimmneg0)), (insn cls:$reg, cls:$reg)>;
+}