[PowerPC] Fix materialization of SP float values on Power10

[lei]

Summary

All floating point values in registers are in double precision
representation. In order to materialize the correct single precision
value, we need to convert the APFloat that represents the value
to double precision first.

[NeHuang]

llvm/lib/Target/PowerPC/PPCInstrInfo.td

415

Do we need to check LosesInfo to ensure lossless conversion?

426

same as above.

[nemanjai]

llvm/lib/Target/PowerPC/PPCInstrInfo.td

415

IIUC It is not possible for a value to be representable in single precision but not double precision. I suppose we can add:
assert(!LosesInfo && "conversion from SP to DP loses info?")

[lei]

change variable name to indicate it's not used.

[amyk]

LGTM.

[NeHuang]

LGTM. Thanks.

llvm/lib/Target/PowerPC/PPCInstrInfo.td

415

Thanks. Agreed. If we decided not adding the assert, maybe just change the

llvm/lib/Target/PowerPC/PPCInstrInfo.td

 def nzFPImmAsi64 : PatLeaf<(fpimm), [{
   APFloat APFloatOfN = N->getValueAPF();
   return !N->isExactlyValue(+0.0) && !checkConvertToNonDenormSingle(APFloatOfN);
 }]>;
 
 // Get the Hi bits of a 64 bit immediate.
 def getFPAs64BitIntHi : SDNodeXForm<fpimm, [{
   APFloat APFloatOfN = N->getValueAPF();
+  bool Unused;
+  APFloatOfN.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
+                     &Unused);
   uint32_t Hi = (uint32_t)((APFloatOfN.bitcastToAPInt().getZExtValue() &
                             0xFFFFFFFF00000000LL) >> 32);
   return CurDAG->getTargetConstant(Hi, SDLoc(N), MVT::i32);
 }]>;
 
 // Get the Lo bits of a 64 bit immediate.
 def getFPAs64BitIntLo : SDNodeXForm<fpimm, [{
   APFloat APFloatOfN = N->getValueAPF();
+  bool Unused;
+  APFloatOfN.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
+                     &Unused);
   uint32_t Lo = (uint32_t)(APFloatOfN.bitcastToAPInt().getZExtValue() &
                            0xFFFFFFFF);
   return CurDAG->getTargetConstant(Lo, SDLoc(N), MVT::i32);
 }]>;
 
 def imm34 : PatLeaf<(imm), [{
   return isInt<34>(N->getSExtValue());
 }]>;

llvm/test/CodeGen/PowerPC/constant-pool.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-- \
 ; RUN:   -mcpu=pwr10 -ppc-asm-full-reg-names < %s | FileCheck %s
 ; RUN: llc -verify-machineinstrs -target-abi=elfv2 -mtriple=powerpc64-- \
 ; RUN:   -mcpu=pwr10 -ppc-asm-full-reg-names < %s | FileCheck %s
 ; RUN: llc -verify-machineinstrs -target-abi=elfv2 -mtriple=powerpc64-- \
 ; RUN:   -mcpu=pwr9 -ppc-asm-full-reg-names < %s | FileCheck %s --check-prefix=CHECK-P9
 
  define float @FloatConstantPool() {
 ; CHECK-LABEL: FloatConstantPool:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    xxsplti32dx vs1, 0, 0
-; CHECK-NEXT:    xxsplti32dx vs1, 1, 8388577
+; CHECK-NEXT:    xxsplti32dx vs1, 0, 940572664
+; CHECK-NEXT:    xxsplti32dx vs1, 1, 1073741824
 ; CHECK-NEXT:    # kill: def $f1 killed $f1 killed $vsl1
 ; CHECK-NEXT:    blr
 ;
 ; CHECK-P9-LABEL: FloatConstantPool:
 ; CHECK-P9:       # %bb.0: # %entry
 ; CHECK-P9-NEXT:    addis r3, r2, .LCPI0_0@toc@ha
 ; CHECK-P9-NEXT:    lfs f1, .LCPI0_0@toc@l(r3)
 ; CHECK-P9-NEXT:    blr

llvm/test/CodeGen/PowerPC/p10-splatImm-CPload-pcrel.ll

 ; CHECK-BE-NEXT:    blr
 entry:
   ret double 3.423300e+02
 }
 
 define dso_local float @testFloatDenormScalar() local_unnamed_addr {
 ; CHECK-LE-LABEL: testFloatDenormScalar:
 ; CHECK-LE:       # %bb.0: # %entry
-; CHECK-LE-NEXT:    xxsplti32dx vs1, 0, 0
-; CHECK-LE-NEXT:    xxsplti32dx vs1, 1, 7136238
+; CHECK-LE-NEXT:    xxsplti32dx vs1, 0, 940259579
+; CHECK-LE-NEXT:    xxsplti32dx vs1, 1, -2147483648
 ; CHECK-LE-NEXT:    # kill: def $f1 killed $f1 killed $vsl1
 ; CHECK-LE-NEXT:    blr
 ;
 ; CHECK-NOPCREL-BE-LABEL: testFloatDenormScalar:
 ; CHECK-NOPCREL-BE:       # %bb.0: # %entry
-; CHECK-NOPCREL-BE-NEXT:    xxsplti32dx vs1, 0, 0
-; CHECK-NOPCREL-BE-NEXT:    xxsplti32dx vs1, 1, 7136238
+; CHECK-NOPCREL-BE-NEXT:    xxsplti32dx vs1, 0, 940259579
+; CHECK-NOPCREL-BE-NEXT:    xxsplti32dx vs1, 1, -2147483648
 ; CHECK-NOPCREL-BE-NEXT:    # kill: def $f1 killed $f1 killed $vsl1
 ; CHECK-NOPCREL-BE-NEXT:    blr
 ;
 ; CHECK-NOPCREL-LE-LABEL: testFloatDenormScalar:
 ; CHECK-NOPCREL-LE:       # %bb.0: # %entry
-; CHECK-NOPCREL-LE-NEXT:    xxsplti32dx vs1, 0, 0
-; CHECK-NOPCREL-LE-NEXT:    xxsplti32dx vs1, 1, 7136238
+; CHECK-NOPCREL-LE-NEXT:    xxsplti32dx vs1, 0, 940259579
+; CHECK-NOPCREL-LE-NEXT:    xxsplti32dx vs1, 1, -2147483648
 ; CHECK-NOPCREL-LE-NEXT:    # kill: def $f1 killed $f1 killed $vsl1
 ; CHECK-NOPCREL-LE-NEXT:    blr
 ;
 ; CHECK-NOPREFIX-LABEL: testFloatDenormScalar:
 ; CHECK-NOPREFIX:       # %bb.0: # %entry
 ; CHECK-NOPREFIX-NEXT:    addis r3, r2, .LCPI4_0@toc@ha
 ; CHECK-NOPREFIX-NEXT:    lfs f1, .LCPI4_0@toc@l(r3)
 ; CHECK-NOPREFIX-NEXT:    blr
 ;
 ; CHECK-BE-LABEL: testFloatDenormScalar:
 ; CHECK-BE:       # %bb.0: # %entry
-; CHECK-BE-NEXT:    xxsplti32dx vs1, 0, 0
-; CHECK-BE-NEXT:    xxsplti32dx vs1, 1, 7136238
+; CHECK-BE-NEXT:    xxsplti32dx vs1, 0, 940259579
+; CHECK-BE-NEXT:    xxsplti32dx vs1, 1, -2147483648
 ; CHECK-BE-NEXT:    # kill: def $f1 killed $f1 killed $vsl1
 ; CHECK-BE-NEXT:    blr
 entry:
   ret float 0x380B38FB80000000
 }
 
 define dso_local double @testFloatDenormToDoubleScalar() local_unnamed_addr {
 ; CHECK-LE-LABEL: testFloatDenormToDoubleScalar: