[llvm] DAG: Add RTLIB::getPOW helper (PR #147274)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/147274

>From d411fcc122eb42f854c825a3a97cfa81676683b2 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 7 Jul 2025 19:33:35 +0900
Subject: [PATCH 1/2] DAG: Add RTLIB::getPOW helper

---
 llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h       |  4 ++++
 llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp | 10 ++++------
 llvm/lib/CodeGen/TargetLoweringBase.cpp              |  4 ++++
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h b/llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h
index 7481ed5b80b3f..451459eda25e9 100644
--- a/llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h
+++ b/llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h
@@ -56,6 +56,10 @@ LLVM_ABI Libcall getUINTTOFP(EVT OpVT, EVT RetVT);
 /// UNKNOWN_LIBCALL if there is none.
 LLVM_ABI Libcall getPOWI(EVT RetVT);
 
+/// getPOW - Return the POW_* value for the given types, or
+/// UNKNOWN_LIBCALL if there is none.
+LLVM_ABI Libcall getPOW(EVT RetVT);
+
 /// getLDEXP - Return the LDEXP_* value for the given types, or
 /// UNKNOWN_LIBCALL if there is none.
 LLVM_ABI Libcall getLDEXP(EVT RetVT);
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index 6a4f983077213..9d9fdeeb8740c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -704,12 +704,7 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_FP_ROUND(SDNode *N) {
 }
 
 SDValue DAGTypeLegalizer::SoftenFloatRes_FPOW(SDNode *N) {
-  return SoftenFloatRes_Binary(N, GetFPLibCall(N->getValueType(0),
-                                               RTLIB::POW_F32,
-                                               RTLIB::POW_F64,
-                                               RTLIB::POW_F80,
-                                               RTLIB::POW_F128,
-                                               RTLIB::POW_PPCF128));
+  return SoftenFloatRes_Binary(N, RTLIB::getPOW(N->getValueType(0)));
 }
 
 SDValue DAGTypeLegalizer::SoftenFloatRes_ExpOp(SDNode *N) {
@@ -723,6 +718,9 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_ExpOp(SDNode *N) {
                              : RTLIB::getLDEXP(N->getValueType(0));
   assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unexpected fpowi.");
   if (!TLI.getLibcallName(LC)) {
+    RTLIB::Libcall NewLC = RTLIB::getPOW(N->getValueType(0));
+    assert(NewLC != RTLIB::UNKNOWN_LIBCALL);
+
     // Some targets don't have a powi libcall; use pow instead.
     // FIXME: Implement this if some target needs it.
     DAG.getContext()->emitError("do not know how to soften fpowi to fpow");
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 65bbec8461a12..4f722005f4056 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -396,6 +396,10 @@ RTLIB::Libcall RTLIB::getPOWI(EVT RetVT) {
                       POWI_PPCF128);
 }
 
+RTLIB::Libcall RTLIB::getPOW(EVT RetVT) {
+  return getFPLibCall(RetVT, POW_F32, POW_F64, POW_F80, POW_F128, POW_PPCF128);
+}
+
 RTLIB::Libcall RTLIB::getLDEXP(EVT RetVT) {
   return getFPLibCall(RetVT, LDEXP_F32, LDEXP_F64, LDEXP_F80, LDEXP_F128,
                       LDEXP_PPCF128);

>From 1c0ddb9d78ccc4c3c5345e8c39651993260752c8 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 7 Jul 2025 21:01:59 +0900
Subject: [PATCH 2/2] Update
 llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

Co-authored-by: Paul Walker <paul.walker at arm.com>
---
 llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index 9d9fdeeb8740c..2a947f3297749 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -719,7 +719,7 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_ExpOp(SDNode *N) {
   assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unexpected fpowi.");
   if (!TLI.getLibcallName(LC)) {
     RTLIB::Libcall NewLC = RTLIB::getPOW(N->getValueType(0));
-    assert(NewLC != RTLIB::UNKNOWN_LIBCALL);
+    assert(NewLC != RTLIB::UNKNOWN_LIBCALL && "Unexpected fpow type");
 
     // Some targets don't have a powi libcall; use pow instead.
     // FIXME: Implement this if some target needs it.