[clang] [llvm] [Clang] Add `__builtin_stack_address` (PR #148281)

[Nikita Popov via llvm-commits]

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@@ -2720,6 +2721,30 @@ static SDValue LowerVAARG(SDValue Op, SelectionDAG &DAG) {
       Align(std::min(PtrVT.getFixedSizeInBits(), VT.getFixedSizeInBits()) / 8));
 }
 
+static SDValue LowerSTACKADDRESS(SDValue Op, SelectionDAG &DAG,
+                                 const SparcSubtarget *Subtarget) {
+  SDValue Chain = Op.getOperand(0);
+  EVT VT = Op->getValueType(0);
+  SDLoc DL(Op);
+  unsigned OffsetToStackStart = 0;
+
+  unsigned SPReg = SP::O6;
+  SDValue SP = DAG.getCopyFromReg(Chain, DL, SPReg, VT);
+
+  // Unbias the stack pointer register.
+  OffsetToStackStart += Subtarget->getStackPointerBias();
+  // Move past the register save area: 8 in registers + 8 local registers.
+  OffsetToStackStart += 16 * (Subtarget->is64Bit() ? 8 : 4);
+  // Move past the struct return address slot (4 bytes) on SPARC 32-bit.
+  if (!Subtarget->is64Bit()) {
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nikic wrote:

No braces for single line if.

https://github.com/llvm/llvm-project/pull/148281