[llvm] [NVPTX] Improve support for {ex2,lg2}.approx (PR #120519)

[Alex MacLean via llvm-commits]

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@@ -1255,18 +1255,33 @@ def INT_NVVM_EX2_APPROX_F : F_MATH_1<"ex2.approx.f32 \t$dst, $src0;",
   Float32Regs, Float32Regs, int_nvvm_ex2_approx_f>;
 def INT_NVVM_EX2_APPROX_D : F_MATH_1<"ex2.approx.f64 \t$dst, $src0;",
   Float64Regs, Float64Regs, int_nvvm_ex2_approx_d>;
+
 def INT_NVVM_EX2_APPROX_F16 : F_MATH_1<"ex2.approx.f16 \t$dst, $src0;",
   Int16Regs, Int16Regs, int_nvvm_ex2_approx_f16, [hasPTX<70>, hasSM<75>]>;
 def INT_NVVM_EX2_APPROX_F16X2 : F_MATH_1<"ex2.approx.f16x2 \t$dst, $src0;",
   Int32Regs, Int32Regs, int_nvvm_ex2_approx_f16x2, [hasPTX<70>, hasSM<75>]>;
 
+def : Pat<(fexp2 f32:$a),
+          (INT_NVVM_EX2_APPROX_FTZ_F $a)>, Requires<[doF32FTZ]>;
+def : Pat<(fexp2 f32:$a),
+          (INT_NVVM_EX2_APPROX_F $a)>, Requires<[doNoF32FTZ]>;
+def : Pat<(fexp2 f16:$a),
+          (INT_NVVM_EX2_APPROX_F16 $a)>, Requires<[useFP16Math]>;
+def : Pat<(fexp2 v2f16:$a),
+          (INT_NVVM_EX2_APPROX_F16X2 $a)>, Requires<[useFP16Math]>;
+
 def INT_NVVM_LG2_APPROX_FTZ_F : F_MATH_1<"lg2.approx.ftz.f32 \t$dst, $src0;",
   Float32Regs, Float32Regs, int_nvvm_lg2_approx_ftz_f>;
 def INT_NVVM_LG2_APPROX_F : F_MATH_1<"lg2.approx.f32 \t$dst, $src0;",
   Float32Regs, Float32Regs, int_nvvm_lg2_approx_f>;
 def INT_NVVM_LG2_APPROX_D : F_MATH_1<"lg2.approx.f64 \t$dst, $src0;",
   Float64Regs, Float64Regs, int_nvvm_lg2_approx_d>;
 
+def : Pat<(flog2 f32:$a), (INT_NVVM_LG2_APPROX_FTZ_F Float32Regs:$a)>,
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AlexMaclean wrote:

Remove redundant register classes here too

https://github.com/llvm/llvm-project/pull/120519