Move the constant-folding support for FP_ROUND in SelectionDAG from the one-operand version of getNode() to the two-operand version, since it became a two-operand node at sound point.

Zap a testcase that this allows us to completely fold away.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154447 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 12 insertions, 19 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6e46d49..92671d1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2428,7 +2428,6 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL,
       case ISD::FABS:
         V.clearSign();
         return getConstantFP(V, VT);
-      case ISD::FP_ROUND:
       case ISD::FP_EXTEND: {
         bool ignored;
         // This can return overflow, underflow, or inexact; we don't care.
@@ -2994,6 +2993,16 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
       default: break;
       }
     }
+
+    if (Opcode == ISD::FP_ROUND) {
+      APFloat V = N1CFP->getValueAPF();    // make copy
+      bool ignored;
+      // This can return overflow, underflow, or inexact; we don't care.
+      // FIXME need to be more flexible about rounding mode.
+      (void)V.convert(*EVTToAPFloatSemantics(VT),
+                      APFloat::rmNearestTiesToEven, &ignored);
+      return getConstantFP(V, VT);
+    }
   }
 
   // Canonicalize an UNDEF to the RHS, even over a constant.
diff --git a/test/CodeGen/ARM/fcopysign.ll b/test/CodeGen/ARM/fcopysign.ll
index 87115cc..27fa2b0 100644
--- a/test/CodeGen/ARM/fcopysign.ll
+++ b/test/CodeGen/ARM/fcopysign.ll
@@ -40,26 +40,10 @@ entry:
   ret double %1
 }
 
-; rdar://9059537
-define i32 @test4() ssp {
-entry:
-; SOFT: test4:
-; SOFT: vmov.f64 [[REG4:(d[0-9]+)]], #1.000000e+00
-; This S-reg must be the first sub-reg of the last D-reg on vbsl.
-; SOFT: vcvt.f32.f64 {{s1?[02468]}}, [[REG4]]
-; SOFT: vshr.u64 [[REG4]], [[REG4]], #32
-; SOFT: vmov.i32 [[REG5:(d[0-9]+)]], #0x80000000
-; SOFT: vbsl [[REG5]], [[REG4]], {{d[0-9]+}}
-  %call80 = tail call double @copysign(double 1.000000e+00, double undef)
-  %conv81 = fptrunc double %call80 to float
-  %tmp88 = bitcast float %conv81 to i32
-  ret i32 %tmp88
-}
-
 ; rdar://9287902
-define float @test5() nounwind {
+define float @test4() nounwind {
 entry:
-; SOFT: test5:
+; SOFT: test4:
 ; SOFT: vmov [[REG7:(d[0-9]+)]], r0, r1
 ; SOFT: vmov.i32 [[REG6:(d[0-9]+)]], #0x80000000
 ; SOFT: vshr.u64 [[REG7]], [[REG7]], #32