[CodeGen] Refactor libcall lookups for RTLIB::POWI_*

Use RuntimeLibcalls to get a common way to pick correct RTLIB::POWI_*
libcall for a given value type.

This includes a small refactoring of ExpandFPLibCall and
ExpandArgFPLibCall in SelectionDAGLegalize to share a bit of code,
plus adding an ExpandFPLibCall version that can be called directly
when expanding FPOWI/STRICT_FPOWI to ensure that we actually use
the same RTLIB::Libcall when expanding the libcall as we used when
checking the legality of such a call by doing a getLibcallName check.

Differential Revision: https://reviews.llvm.org/D103050

1 files changed, 22 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 02eb9a5..4f91a84 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -211,6 +211,23 @@ void TargetLoweringBase::InitLibcalls(const Triple &TT) {
   }
 }
 
+/// GetFPLibCall - Helper to return the right libcall for the given floating
+/// point type, or UNKNOWN_LIBCALL if there is none.
+RTLIB::Libcall RTLIB::getFPLibCall(EVT VT,
+                                   RTLIB::Libcall Call_F32,
+                                   RTLIB::Libcall Call_F64,
+                                   RTLIB::Libcall Call_F80,
+                                   RTLIB::Libcall Call_F128,
+                                   RTLIB::Libcall Call_PPCF128) {
+  return
+    VT == MVT::f32 ? Call_F32 :
+    VT == MVT::f64 ? Call_F64 :
+    VT == MVT::f80 ? Call_F80 :
+    VT == MVT::f128 ? Call_F128 :
+    VT == MVT::ppcf128 ? Call_PPCF128 :
+    RTLIB::UNKNOWN_LIBCALL;
+}
+
 /// getFPEXT - Return the FPEXT_*_* value for the given types, or
 /// UNKNOWN_LIBCALL if there is none.
 RTLIB::Libcall RTLIB::getFPEXT(EVT OpVT, EVT RetVT) {
@@ -469,6 +486,11 @@ RTLIB::Libcall RTLIB::getUINTTOFP(EVT OpVT, EVT RetVT) {
   return UNKNOWN_LIBCALL;
 }
 
+RTLIB::Libcall RTLIB::getPOWI(EVT RetVT) {
+  return getFPLibCall(RetVT, POWI_F32, POWI_F64, POWI_F80, POWI_F128,
+                      POWI_PPCF128);
+}
+
 RTLIB::Libcall RTLIB::getOUTLINE_ATOMIC(unsigned Opc, AtomicOrdering Order,
                                         MVT VT) {
   unsigned ModeN, ModelN;