[llvm] [X86][GlobalISel] Added support for llvm.get.rounding (PR #147716)

via llvm-commits llvm-commits at lists.llvm.org
Wed Jul 9 05:59:30 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: None (JaydeepChauhan14)

<details>
<summary>Changes</summary>

- This implementation is copied from SDAG **X86TargetLowering::LowerSET_ROUNDING**.
- Set rounding mode will be added later because of SSE differences.

---

Patch is 26.73 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/147716.diff


10 Files Affected:

- (modified) llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h (+5) 
- (modified) llvm/include/llvm/Support/TargetOpcodes.def (+2) 
- (modified) llvm/include/llvm/Target/GenericOpcodes.td (+6) 
- (modified) llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp (+3) 
- (modified) llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp (+81) 
- (modified) llvm/lib/Target/X86/GISel/X86LegalizerInfo.h (+3) 
- (modified) llvm/lib/Target/X86/X86InstrGISel.td (+8) 
- (modified) llvm/test/CodeGen/X86/flt-rounds.ll (+307-135) 
- (modified) llvm/test/MC/ELF/mc-dump.s (+1-1) 
- (modified) llvm/test/TableGen/GlobalISelEmitter/GlobalISelEmitter.td (+1-1) 


``````````diff
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h b/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
index 25fef99699fdf..01b94ac7218a5 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h
@@ -2382,6 +2382,11 @@ class LLVM_ABI MachineIRBuilder {
     return buildInstr(TargetOpcode::G_RESET_FPMODE, {}, {});
   }
 
+  /// Build and insert \p Dst = G_GET_ROUNDING
+  MachineInstrBuilder buildGetRounding(const DstOp &Dst) {
+    return buildInstr(TargetOpcode::G_GET_ROUNDING, {Dst}, {});
+  }
+
   virtual MachineInstrBuilder
   buildInstr(unsigned Opc, ArrayRef<DstOp> DstOps, ArrayRef<SrcOp> SrcOps,
              std::optional<unsigned> Flags = std::nullopt);
diff --git a/llvm/include/llvm/Support/TargetOpcodes.def b/llvm/include/llvm/Support/TargetOpcodes.def
index 92fd60e03112a..5dfa1d5095b86 100644
--- a/llvm/include/llvm/Support/TargetOpcodes.def
+++ b/llvm/include/llvm/Support/TargetOpcodes.def
@@ -735,6 +735,8 @@ HANDLE_TARGET_OPCODE(G_GET_FPMODE)
 HANDLE_TARGET_OPCODE(G_SET_FPMODE)
 HANDLE_TARGET_OPCODE(G_RESET_FPMODE)
 
+HANDLE_TARGET_OPCODE(G_GET_ROUNDING)
+
 /// Generic pointer offset
 HANDLE_TARGET_OPCODE(G_PTR_ADD)
 
diff --git a/llvm/include/llvm/Target/GenericOpcodes.td b/llvm/include/llvm/Target/GenericOpcodes.td
index a462b07461b41..a4a23cde42335 100644
--- a/llvm/include/llvm/Target/GenericOpcodes.td
+++ b/llvm/include/llvm/Target/GenericOpcodes.td
@@ -1246,6 +1246,12 @@ def G_READSTEADYCOUNTER : GenericInstruction {
   let hasSideEffects = true;
 }
 
+def G_GET_ROUNDING : GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins);
+  let hasSideEffects = true;
+}
+
 //------------------------------------------------------------------------------
 // Memory ops
 //------------------------------------------------------------------------------
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index ef39fc74554c9..d7280eaba2440 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2593,6 +2593,9 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
   case Intrinsic::reset_fpmode:
     MIRBuilder.buildResetFPMode();
     return true;
+  case Intrinsic::get_rounding:
+    MIRBuilder.buildGetRounding(getOrCreateVReg(CI));
+    return true;
   case Intrinsic::vscale: {
     MIRBuilder.buildVScale(getOrCreateVReg(CI), 1);
     return true;
diff --git a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp
index 8e304c07ed5cb..7fe58539cd4ec 100644
--- a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp
+++ b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp
@@ -17,6 +17,7 @@
 #include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/IR/DerivedTypes.h"
@@ -108,6 +109,8 @@ X86LegalizerInfo::X86LegalizerInfo(const X86Subtarget &STI,
       .legalFor(HasSSE2 || UseX87, {s64})
       .legalFor(UseX87, {s80});
 
+  getActionDefinitionsBuilder(G_GET_ROUNDING).customFor({s32});
+
   // merge/unmerge
   for (unsigned Op : {G_MERGE_VALUES, G_UNMERGE_VALUES}) {
     unsigned BigTyIdx = Op == G_MERGE_VALUES ? 0 : 1;
@@ -611,6 +614,8 @@ bool X86LegalizerInfo::legalizeCustom(LegalizerHelper &Helper, MachineInstr &MI,
     return legalizeSITOFP(MI, MRI, Helper);
   case TargetOpcode::G_FPTOSI:
     return legalizeFPTOSI(MI, MRI, Helper);
+  case TargetOpcode::G_GET_ROUNDING:
+    return legalizeGETROUNDING(MI, MRI, Helper);
   }
   llvm_unreachable("expected switch to return");
 }
@@ -777,6 +782,82 @@ bool X86LegalizerInfo::legalizeNarrowingStore(MachineInstr &MI,
   return true;
 }
 
+bool X86LegalizerInfo::legalizeGETROUNDING(MachineInstr &MI,
+                                           MachineRegisterInfo &MRI,
+                                           LegalizerHelper &Helper) const {
+  /*
+   The rounding mode is in bits 11:10 of FPSR, and has the following
+   settings:
+     00 Round to nearest
+     01 Round to -inf
+     10 Round to +inf
+     11 Round to 0
+
+  GET_ROUNDING, on the other hand, expects the following:
+    -1 Undefined
+     0 Round to 0
+     1 Round to nearest
+     2 Round to +inf
+     3 Round to -inf
+
+  To perform the conversion, we use a packed lookup table of the four 2-bit
+  values that we can index by FPSP[11:10]
+    0x2d --> (0b00,10,11,01) --> (0,2,3,1) >> FPSR[11:10]
+
+    (0x2d >> ((FPSR >> 9) & 6)) & 3
+  */
+
+  MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
+  MachineFunction &MF = MIRBuilder.getMF();
+  Register Dst = MI.getOperand(0).getReg();
+  LLT DstTy = MRI.getType(Dst);
+  const LLT s8 = LLT::scalar(8);
+  const LLT s16 = LLT::scalar(16);
+  const LLT s32 = LLT::scalar(32);
+
+  // Save FP Control Word to stack slot
+  int MemSize = 2;
+  Align Alignment = Align(2);
+  MachinePointerInfo PtrInfo;
+  auto StackTemp = Helper.createStackTemporary(TypeSize::getFixed(MemSize),
+                                               Alignment, PtrInfo);
+  Register StackPtr = StackTemp.getReg(0);
+
+  auto StoreMMO = MF.getMachineMemOperand(PtrInfo, MachineMemOperand::MOStore,
+                                          MemSize, Alignment);
+
+  // Store FP Control Word to stack slot using G_FNSTCW16
+  MIRBuilder.buildInstr(X86::G_FNSTCW16)
+      .addUse(StackPtr)
+      .addMemOperand(StoreMMO);
+
+  // Load FP Control Word from stack slot
+  auto LoadMMO = MF.getMachineMemOperand(PtrInfo, MachineMemOperand::MOLoad,
+                                         MemSize, Alignment);
+
+  auto CWD32 =
+      MIRBuilder.buildZExt(s32, MIRBuilder.buildLoad(s16, StackPtr, *LoadMMO));
+  auto Shifted8 = MIRBuilder.buildTrunc(
+      s8, MIRBuilder.buildLShr(s32, CWD32, MIRBuilder.buildConstant(s8, 9)));
+  auto Masked32 = MIRBuilder.buildZExt(
+      s32, MIRBuilder.buildAnd(s8, Shifted8, MIRBuilder.buildConstant(s8, 6)));
+
+  // LUT is a packed lookup table (0x2d) used to map the 2-bit x87 FPU rounding
+  // mode (from bits 11:10 of the control word) to the values expected by
+  // GET_ROUNDING. The mapping is performed by shifting LUT right by the
+  // extracted rounding mode and masking the result with 3 to obtain the final
+  auto LUT = MIRBuilder.buildConstant(s32, 0x2d);
+  auto LUTShifted = MIRBuilder.buildLShr(s32, LUT, Masked32);
+  auto RetVal =
+      MIRBuilder.buildAnd(s32, LUTShifted, MIRBuilder.buildConstant(s32, 3));
+  auto RetValTrunc = MIRBuilder.buildZExtOrTrunc(DstTy, RetVal);
+
+  MIRBuilder.buildCopy(Dst, RetValTrunc);
+
+  MI.eraseFromParent();
+  return true;
+}
+
 bool X86LegalizerInfo::legalizeIntrinsic(LegalizerHelper &Helper,
                                          MachineInstr &MI) const {
   return true;
diff --git a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h
index 1ba82674ed4c6..0003552d70ee0 100644
--- a/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h
+++ b/llvm/lib/Target/X86/GISel/X86LegalizerInfo.h
@@ -54,6 +54,9 @@ class X86LegalizerInfo : public LegalizerInfo {
 
   bool legalizeFPTOSI(MachineInstr &MI, MachineRegisterInfo &MRI,
                       LegalizerHelper &Helper) const;
+
+  bool legalizeGETROUNDING(MachineInstr &MI, MachineRegisterInfo &MRI,
+                           LegalizerHelper &Helper) const;
 };
 } // namespace llvm
 #endif
diff --git a/llvm/lib/Target/X86/X86InstrGISel.td b/llvm/lib/Target/X86/X86InstrGISel.td
index f4fa33807cd9a..39198214037a3 100644
--- a/llvm/lib/Target/X86/X86InstrGISel.td
+++ b/llvm/lib/Target/X86/X86InstrGISel.td
@@ -27,5 +27,13 @@ def G_FIST : X86GenericInstruction {
   let mayStore = true;
 }
 
+def G_FNSTCW16 : X86GenericInstruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins ptype0:$dst);
+  let hasSideEffects = true;
+  let mayStore = true;
+}
+
 def : GINodeEquiv<G_FILD, X86fild>;
 def : GINodeEquiv<G_FIST, X86fp_to_mem>;
+def : GINodeEquiv<G_FNSTCW16, X86fp_cwd_get16>;
diff --git a/llvm/test/CodeGen/X86/flt-rounds.ll b/llvm/test/CodeGen/X86/flt-rounds.ll
index a5908978a5438..1d7a8d8456c27 100644
--- a/llvm/test/CodeGen/X86/flt-rounds.ll
+++ b/llvm/test/CodeGen/X86/flt-rounds.ll
@@ -1,7 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=-sse -verify-machineinstrs < %s | FileCheck %s --check-prefix=X86
-; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=-sse2 -verify-machineinstrs < %s | FileCheck %s --check-prefix=X86
-; RUN: llc -mtriple=x86_64-unknown-linux-gnu -verify-machineinstrs < %s | FileCheck %s --check-prefix=X64
+; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=-sse -verify-machineinstrs < %s | FileCheck %s --check-prefixes=X86,SDAG-X86
+; RUN: llc -mtriple=i686-unknown-linux-gnu -mattr=-sse2 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=X86,SDAG-X86
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -verify-machineinstrs < %s | FileCheck %s --check-prefixes=X64,SDAG-X64
+; RUN: llc -mtriple=i686-unknown-linux-gnu   -global-isel=1 -global-isel-abort=1 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=X86,GISEL-X86
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -global-isel=1 -global-isel-abort=1 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=X64,GISEL-X64
 
 declare i32 @llvm.get.rounding()
 
@@ -37,139 +39,309 @@ define i32 @test_flt_rounds() nounwind {
 
 ; Make sure we preserve order with fesetround.
 define i32 @multiple_flt_rounds() nounwind {
-; X86-LABEL: multiple_flt_rounds:
-; X86:       # %bb.0: # %entry
-; X86-NEXT:    pushl %ebx
-; X86-NEXT:    pushl %esi
-; X86-NEXT:    subl $20, %esp
-; X86-NEXT:    movl $1024, (%esp) # imm = 0x400
-; X86-NEXT:    calll fesetround
-; X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
-; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    shrl $9, %ecx
-; X86-NEXT:    andb $6, %cl
-; X86-NEXT:    movl $45, %esi
-; X86-NEXT:    movl $45, %eax
-; X86-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-NEXT:    shrl %cl, %eax
-; X86-NEXT:    andl $3, %eax
-; X86-NEXT:    xorl %ebx, %ebx
-; X86-NEXT:    cmpl $3, %eax
-; X86-NEXT:    setne %bl
-; X86-NEXT:    movl $0, (%esp)
-; X86-NEXT:    calll fesetround
-; X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
-; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    shrl $9, %ecx
-; X86-NEXT:    andb $6, %cl
-; X86-NEXT:    movl $45, %eax
-; X86-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-NEXT:    shrl %cl, %eax
-; X86-NEXT:    andl $3, %eax
-; X86-NEXT:    cmpl $1, %eax
-; X86-NEXT:    je .LBB1_2
-; X86-NEXT:  # %bb.1: # %entry
-; X86-NEXT:    incl %ebx
-; X86-NEXT:  .LBB1_2: # %entry
-; X86-NEXT:    movl $3072, (%esp) # imm = 0xC00
-; X86-NEXT:    calll fesetround
-; X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
-; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    shrl $9, %ecx
-; X86-NEXT:    andb $6, %cl
-; X86-NEXT:    movl $45, %eax
-; X86-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-NEXT:    shrl %cl, %eax
-; X86-NEXT:    andl $3, %eax
-; X86-NEXT:    cmpl $1, %eax
-; X86-NEXT:    sbbl $-1, %ebx
-; X86-NEXT:    movl $2048, (%esp) # imm = 0x800
-; X86-NEXT:    calll fesetround
-; X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
-; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    shrl $9, %ecx
-; X86-NEXT:    andb $6, %cl
-; X86-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-NEXT:    shrl %cl, %esi
-; X86-NEXT:    andl $3, %esi
-; X86-NEXT:    xorl %ecx, %ecx
-; X86-NEXT:    cmpl $2, %esi
-; X86-NEXT:    setne %cl
-; X86-NEXT:    negl %ecx
-; X86-NEXT:    xorl %eax, %eax
-; X86-NEXT:    cmpl %ecx, %ebx
-; X86-NEXT:    setne %al
-; X86-NEXT:    addl $20, %esp
-; X86-NEXT:    popl %esi
-; X86-NEXT:    popl %ebx
-; X86-NEXT:    retl
+; SDAG-X86-LABEL: multiple_flt_rounds:
+; SDAG-X86:       # %bb.0: # %entry
+; SDAG-X86-NEXT:    pushl %ebx
+; SDAG-X86-NEXT:    pushl %esi
+; SDAG-X86-NEXT:    subl $20, %esp
+; SDAG-X86-NEXT:    movl $1024, (%esp) # imm = 0x400
+; SDAG-X86-NEXT:    calll fesetround
+; SDAG-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; SDAG-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; SDAG-X86-NEXT:    shrl $9, %ecx
+; SDAG-X86-NEXT:    andb $6, %cl
+; SDAG-X86-NEXT:    movl $45, %esi
+; SDAG-X86-NEXT:    movl $45, %eax
+; SDAG-X86-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X86-NEXT:    shrl %cl, %eax
+; SDAG-X86-NEXT:    andl $3, %eax
+; SDAG-X86-NEXT:    xorl %ebx, %ebx
+; SDAG-X86-NEXT:    cmpl $3, %eax
+; SDAG-X86-NEXT:    setne %bl
+; SDAG-X86-NEXT:    movl $0, (%esp)
+; SDAG-X86-NEXT:    calll fesetround
+; SDAG-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; SDAG-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; SDAG-X86-NEXT:    shrl $9, %ecx
+; SDAG-X86-NEXT:    andb $6, %cl
+; SDAG-X86-NEXT:    movl $45, %eax
+; SDAG-X86-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X86-NEXT:    shrl %cl, %eax
+; SDAG-X86-NEXT:    andl $3, %eax
+; SDAG-X86-NEXT:    cmpl $1, %eax
+; SDAG-X86-NEXT:    je .LBB1_2
+; SDAG-X86-NEXT:  # %bb.1: # %entry
+; SDAG-X86-NEXT:    incl %ebx
+; SDAG-X86-NEXT:  .LBB1_2: # %entry
+; SDAG-X86-NEXT:    movl $3072, (%esp) # imm = 0xC00
+; SDAG-X86-NEXT:    calll fesetround
+; SDAG-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; SDAG-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; SDAG-X86-NEXT:    shrl $9, %ecx
+; SDAG-X86-NEXT:    andb $6, %cl
+; SDAG-X86-NEXT:    movl $45, %eax
+; SDAG-X86-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X86-NEXT:    shrl %cl, %eax
+; SDAG-X86-NEXT:    andl $3, %eax
+; SDAG-X86-NEXT:    cmpl $1, %eax
+; SDAG-X86-NEXT:    sbbl $-1, %ebx
+; SDAG-X86-NEXT:    movl $2048, (%esp) # imm = 0x800
+; SDAG-X86-NEXT:    calll fesetround
+; SDAG-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; SDAG-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; SDAG-X86-NEXT:    shrl $9, %ecx
+; SDAG-X86-NEXT:    andb $6, %cl
+; SDAG-X86-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X86-NEXT:    shrl %cl, %esi
+; SDAG-X86-NEXT:    andl $3, %esi
+; SDAG-X86-NEXT:    xorl %ecx, %ecx
+; SDAG-X86-NEXT:    cmpl $2, %esi
+; SDAG-X86-NEXT:    setne %cl
+; SDAG-X86-NEXT:    negl %ecx
+; SDAG-X86-NEXT:    xorl %eax, %eax
+; SDAG-X86-NEXT:    cmpl %ecx, %ebx
+; SDAG-X86-NEXT:    setne %al
+; SDAG-X86-NEXT:    addl $20, %esp
+; SDAG-X86-NEXT:    popl %esi
+; SDAG-X86-NEXT:    popl %ebx
+; SDAG-X86-NEXT:    retl
 ;
-; X64-LABEL: multiple_flt_rounds:
-; X64:       # %bb.0: # %entry
-; X64-NEXT:    pushq %rbp
-; X64-NEXT:    pushq %r14
-; X64-NEXT:    pushq %rbx
-; X64-NEXT:    subq $16, %rsp
-; X64-NEXT:    movl $1024, %edi # imm = 0x400
-; X64-NEXT:    callq fesetround
-; X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
-; X64-NEXT:    shrl $9, %ecx
-; X64-NEXT:    andb $6, %cl
-; X64-NEXT:    movl $45, %ebx
-; X64-NEXT:    movl $45, %eax
-; X64-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-NEXT:    shrl %cl, %eax
-; X64-NEXT:    andl $3, %eax
-; X64-NEXT:    xorl %r14d, %r14d
-; X64-NEXT:    cmpl $3, %eax
-; X64-NEXT:    setne %r14b
-; X64-NEXT:    xorl %edi, %edi
-; X64-NEXT:    callq fesetround
-; X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
-; X64-NEXT:    shrl $9, %ecx
-; X64-NEXT:    andb $6, %cl
-; X64-NEXT:    movl $45, %eax
-; X64-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-NEXT:    shrl %cl, %eax
-; X64-NEXT:    andl $3, %eax
-; X64-NEXT:    leal 1(%r14), %ebp
-; X64-NEXT:    cmpl $1, %eax
-; X64-NEXT:    cmovel %r14d, %ebp
-; X64-NEXT:    movl $3072, %edi # imm = 0xC00
-; X64-NEXT:    callq fesetround
-; X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
-; X64-NEXT:    shrl $9, %ecx
-; X64-NEXT:    andb $6, %cl
-; X64-NEXT:    movl $45, %eax
-; X64-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-NEXT:    shrl %cl, %eax
-; X64-NEXT:    andl $3, %eax
-; X64-NEXT:    cmpl $1, %eax
-; X64-NEXT:    sbbl $-1, %ebp
-; X64-NEXT:    movl $2048, %edi # imm = 0x800
-; X64-NEXT:    callq fesetround
-; X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
-; X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
-; X64-NEXT:    shrl $9, %ecx
-; X64-NEXT:    andb $6, %cl
-; X64-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-NEXT:    shrl %cl, %ebx
-; X64-NEXT:    andl $3, %ebx
-; X64-NEXT:    xorl %ecx, %ecx
-; X64-NEXT:    cmpl $2, %ebx
-; X64-NEXT:    setne %cl
-; X64-NEXT:    negl %ecx
-; X64-NEXT:    xorl %eax, %eax
-; X64-NEXT:    cmpl %ecx, %ebp
-; X64-NEXT:    setne %al
-; X64-NEXT:    addq $16, %rsp
-; X64-NEXT:    popq %rbx
-; X64-NEXT:    popq %r14
-; X64-NEXT:    popq %rbp
-; X64-NEXT:    retq
+; SDAG-X64-LABEL: multiple_flt_rounds:
+; SDAG-X64:       # %bb.0: # %entry
+; SDAG-X64-NEXT:    pushq %rbp
+; SDAG-X64-NEXT:    pushq %r14
+; SDAG-X64-NEXT:    pushq %rbx
+; SDAG-X64-NEXT:    subq $16, %rsp
+; SDAG-X64-NEXT:    movl $1024, %edi # imm = 0x400
+; SDAG-X64-NEXT:    callq fesetround
+; SDAG-X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
+; SDAG-X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
+; SDAG-X64-NEXT:    shrl $9, %ecx
+; SDAG-X64-NEXT:    andb $6, %cl
+; SDAG-X64-NEXT:    movl $45, %ebx
+; SDAG-X64-NEXT:    movl $45, %eax
+; SDAG-X64-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X64-NEXT:    shrl %cl, %eax
+; SDAG-X64-NEXT:    andl $3, %eax
+; SDAG-X64-NEXT:    xorl %r14d, %r14d
+; SDAG-X64-NEXT:    cmpl $3, %eax
+; SDAG-X64-NEXT:    setne %r14b
+; SDAG-X64-NEXT:    xorl %edi, %edi
+; SDAG-X64-NEXT:    callq fesetround
+; SDAG-X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
+; SDAG-X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
+; SDAG-X64-NEXT:    shrl $9, %ecx
+; SDAG-X64-NEXT:    andb $6, %cl
+; SDAG-X64-NEXT:    movl $45, %eax
+; SDAG-X64-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X64-NEXT:    shrl %cl, %eax
+; SDAG-X64-NEXT:    andl $3, %eax
+; SDAG-X64-NEXT:    leal 1(%r14), %ebp
+; SDAG-X64-NEXT:    cmpl $1, %eax
+; SDAG-X64-NEXT:    cmovel %r14d, %ebp
+; SDAG-X64-NEXT:    movl $3072, %edi # imm = 0xC00
+; SDAG-X64-NEXT:    callq fesetround
+; SDAG-X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
+; SDAG-X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
+; SDAG-X64-NEXT:    shrl $9, %ecx
+; SDAG-X64-NEXT:    andb $6, %cl
+; SDAG-X64-NEXT:    movl $45, %eax
+; SDAG-X64-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X64-NEXT:    shrl %cl, %eax
+; SDAG-X64-NEXT:    andl $3, %eax
+; SDAG-X64-NEXT:    cmpl $1, %eax
+; SDAG-X64-NEXT:    sbbl $-1, %ebp
+; SDAG-X64-NEXT:    movl $2048, %edi # imm = 0x800
+; SDAG-X64-NEXT:    callq fesetround
+; SDAG-X64-NEXT:    fnstcw {{[0-9]+}}(%rsp)
+; SDAG-X64-NEXT:    movzwl {{[0-9]+}}(%rsp), %ecx
+; SDAG-X64-NEXT:    shrl $9, %ecx
+; SDAG-X64-NEXT:    andb $6, %cl
+; SDAG-X64-NEXT:    # kill: def $cl killed $cl killed $ecx
+; SDAG-X64-NEXT:    shrl %cl, %ebx
+; SDAG-X64-NEXT:    andl $3, %ebx
+; SDAG-X64-NEXT:    xorl %ecx, %ecx
+; SDAG-X64-NEXT:    cmpl $2, %ebx
+; SDAG-X64-NEXT:    setne %cl
+; SDAG-X64-NEXT:    negl %ecx
+; SDAG-X64-NEXT:    xorl %eax, %eax
+; SDAG-X64-NEXT:    cmpl %ecx, %ebp
+; SDAG-X64-NEXT:    setne %al
+; SDAG-X64-NEXT:    addq $16, %rsp
+; SDAG-X64-NEXT:    popq %rbx
+; SDAG-X64-NEXT:    popq %r14
+; SDAG-X64-NEXT:    popq %rbp
+; SDAG-X64-NEXT:    retq
+;
+; GISEL-X86-LABEL: multiple_flt_rounds:
+; GISEL-X86:       # %bb.0: # %entry
+; GISEL-X86-NEXT:    pushl %ebp
+; GISEL-X86-NEXT:    pushl %ebx
+; GISEL-X86-NEXT:    pushl %edi
+; GISEL-X86-NEXT:    pushl %esi
+; GISEL-X86-NEXT:    subl $12, %esp
+; GISEL-X86-NEXT:    movl $1, %ebp
+; GISEL-X86-NEXT:    movl $1024, (%esp) # imm = 0x400
+; GISEL-X86-NEXT:    calll fesetround
+; GISEL-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; GISEL-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; GISEL-X86-NEXT:    shrl $9, %ecx
+; GISEL-X86-NEXT:    andb $6, %cl
+; GISEL-X86-NEXT:    movl $45, %edi
+; GISEL-X86-NEXT:    movl $45, %eax
+; GISEL-X86-NEXT:    # kill: def $cl killed $cl killed $ecx
+; GISEL-X86-NEXT:    shrl %cl, %eax
+; GISEL-X86-NEXT:    andl $3, %eax
+; GISEL-X86-NEXT:    xorl %ebx, %ebx
+; GISEL-X86-NEXT:    cmpl $3, %eax
+; GISEL-X86-NEXT:    setne %bl
+; GISEL-X86-NEXT:    andl $1, %ebx
+; GISEL-X86-NEXT:    movl $0, (%esp)
+; GISEL-X86-NEXT:    calll fesetround
+; GISEL-X86-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; GISEL-X86-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; GISEL-X...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/147716


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