AMDGPU: Fix v2i64/v2f64 bitcasts

[arsenm]

Summary

These operations tend to get promoted away to v4i32 so
this doesn't happen often.

[• tstellarAMD]

LGTM.

[arsenm]

r270741

lib/Target/AMDGPU/SIInstructions.td

 
 // 128-bit bitcast
 def : BitConvert <v2i64, v4i32, SReg_128>;
 def : BitConvert <v4i32, v2i64, SReg_128>;
 def : BitConvert <v2f64, v4f32, VReg_128>;
 def : BitConvert <v2f64, v4i32, VReg_128>;
 def : BitConvert <v4f32, v2f64, VReg_128>;
 def : BitConvert <v4i32, v2f64, VReg_128>;
+def : BitConvert <v2i64, v2f64, VReg_128>;
+def : BitConvert <v2f64, v2i64, VReg_128>;
 
 // 256-bit bitcast
 def : BitConvert <v8i32, v8f32, SReg_256>;
 def : BitConvert <v8f32, v8i32, SReg_256>;
 def : BitConvert <v8i32, v8f32, VReg_256>;
 def : BitConvert <v8f32, v8i32, VReg_256>;
 
 // 512-bit bitcast

test/CodeGen/AMDGPU/bitcast.ll

-; RUN: llc -march=amdgcn -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 ; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 
 ; This test just checks that the compiler doesn't crash.
 
 declare void @llvm.SI.export(i32, i32, i32, i32, i32, float, float, float, float)
 
 ; FUNC-LABEL: {{^}}v32i8_to_v8i32:
 ; SI: s_endpgm

 ; SI: s_endpgm
 define void @bitcast_f64_to_v2i32(<2 x i32> addrspace(1)* %out, double addrspace(1)* %in) {
   %val = load double, double addrspace(1)* %in, align 8
   %add = fadd double %val, 4.0
   %bc = bitcast double %add to <2 x i32>
   store <2 x i32> %bc, <2 x i32> addrspace(1)* %out, align 8
   ret void
 }
+
+; FUNC-LABEL: {{^}}bitcast_v2i64_to_v2f64:
+define void @bitcast_v2i64_to_v2f64(i32 %cond, <2 x double> addrspace(1)* %out, <2 x i64> %value) {
+entry:
+  %cmp0 = icmp eq i32 %cond, 0
+  br i1 %cmp0, label %if, label %end
+
+if:
+  %cast = bitcast <2 x i64> %value to <2 x double>
+  br label %end
+
+end:
+  %phi = phi <2 x double> [zeroinitializer, %entry], [%cast, %if]
+  store <2 x double> %phi, <2 x double> addrspace(1)* %out
+  ret void
+}
+
+; FUNC-LABEL: {{^}}bitcast_v2f64_to_v2i64:
+define void @bitcast_v2f64_to_v2i64(i32 %cond, <2 x i64> addrspace(1)* %out, <2 x double> %value) {
+entry:
+  %cmp0 = icmp eq i32 %cond, 0
+  br i1 %cmp0, label %if, label %end
+
+if:
+  %cast = bitcast <2 x double> %value to <2 x i64>
+  br label %end
+
+end:
+  %phi = phi <2 x i64> [zeroinitializer, %entry], [%cast, %if]
+  store <2 x i64> %phi, <2 x i64> addrspace(1)* %out
+  ret void
+}