[llvm-branch-commits] [llvm] RuntimeLibcalls: Invert handling of 64-bit only libcalls (PR #148571)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

Switch the default set to exclude these conditionally available
calls, so they are opt-in instead of opt-out.

---
Full diff: https://github.com/llvm/llvm-project/pull/148571.diff


2 Files Affected:

- (modified) llvm/include/llvm/IR/RuntimeLibcalls.td (+5-5) 
- (modified) llvm/lib/IR/RuntimeLibcalls.cpp (+11-9) 


``````````diff
diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index 53eea97bf1ea9..b0651a8ac9920 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -439,26 +439,21 @@ let IsDefault = true in {
 def __ashlhi3 : RuntimeLibcallImpl<SHL_I16>;
 def __ashlsi3 : RuntimeLibcallImpl<SHL_I32>;
 def __ashldi3 : RuntimeLibcallImpl<SHL_I64>;
-def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
 
 def __lshrhi3 : RuntimeLibcallImpl<SRL_I16>;
 def __lshrsi3 : RuntimeLibcallImpl<SRL_I32>;
 def __lshrdi3 : RuntimeLibcallImpl<SRL_I64>;
-def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
 
 def __ashrhi3 : RuntimeLibcallImpl<SRA_I16>;
 def __ashrsi3 : RuntimeLibcallImpl<SRA_I32>;
 def __ashrdi3 : RuntimeLibcallImpl<SRA_I64>;
-def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
 
 def __mulqi3 : RuntimeLibcallImpl<MUL_I8>;
 def __mulhi3 : RuntimeLibcallImpl<MUL_I16>;
 def __mulsi3 : RuntimeLibcallImpl<MUL_I32>;
 def __muldi3 : RuntimeLibcallImpl<MUL_I64>;
-def __multi3 : RuntimeLibcallImpl<MUL_I128>;
 
 def __mulosi4 : RuntimeLibcallImpl<MULO_I32>;
-def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
 
 def __divqi3 : RuntimeLibcallImpl<SDIV_I8>;
 def __divhi3 : RuntimeLibcallImpl<SDIV_I16>;
@@ -938,6 +933,11 @@ def calloc : RuntimeLibcallImpl<CALLOC>;
 // compiler-rt, not available for most architectures
 //--------------------------------------------------------------------
 
+def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
+def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
+def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
+def __multi3 : RuntimeLibcallImpl<MUL_I128>;
+def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
 def __muloti4 : RuntimeLibcallImpl<MULO_I128>;
 
 //--------------------------------------------------------------------
diff --git a/llvm/lib/IR/RuntimeLibcalls.cpp b/llvm/lib/IR/RuntimeLibcalls.cpp
index 3dd894ad6c50e..004d2758cb963 100644
--- a/llvm/lib/IR/RuntimeLibcalls.cpp
+++ b/llvm/lib/IR/RuntimeLibcalls.cpp
@@ -139,6 +139,10 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
                                        EABI EABIVersion, StringRef ABIName) {
   setTargetRuntimeLibcallSets(TT, FloatABI);
 
+  // Early exit for targets that have fully ported to tablegen.
+  if (TT.isAMDGPU() || TT.isNVPTX())
+    return;
+
   // Use the f128 variants of math functions on x86
   if (TT.isX86() && TT.isGNUEnvironment())
     setLongDoubleIsF128Libm(*this, /*FiniteOnlyFuncs=*/true);
@@ -241,15 +245,13 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
   if (TT.isARM() || TT.isThumb())
     setARMLibcallNames(*this, TT, FloatABI, EABIVersion);
 
-  if (!TT.isWasm()) {
-    // These libcalls are only available in compiler-rt, not libgcc.
-    if (TT.isArch32Bit()) {
-      setLibcallImpl(RTLIB::SHL_I128, RTLIB::Unsupported);
-      setLibcallImpl(RTLIB::SRL_I128, RTLIB::Unsupported);
-      setLibcallImpl(RTLIB::SRA_I128, RTLIB::Unsupported);
-      setLibcallImpl(RTLIB::MUL_I128, RTLIB::Unsupported);
-      setLibcallImpl(RTLIB::MULO_I64, RTLIB::Unsupported);
-    }
+  // These libcalls are only available in compiler-rt, not libgcc.
+  if (TT.isArch64Bit()) {
+    setLibcallImpl(RTLIB::SHL_I128, RTLIB::__ashlti3);
+    setLibcallImpl(RTLIB::SRL_I128, RTLIB::__lshrti3);
+    setLibcallImpl(RTLIB::SRA_I128, RTLIB::__ashrti3);
+    setLibcallImpl(RTLIB::MUL_I128, RTLIB::__multi3);
+    setLibcallImpl(RTLIB::MULO_I64, RTLIB::__mulodi4);
   }
 
   if (TT.getArch() == Triple::ArchType::msp430) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/148571