Subzero: Legalize FP constants directly into memory operands.

tests_lit/llvm2ice_tests/bitcast.ll

 ; Trivial smoke test of bitcast between integer and FP types.
 
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -O2 | FileCheck %s
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -Om1 | FileCheck %s
 
 define internal i32 @cast_f2i(float %f) {
 entry:
   %v0 = bitcast float %f to i32
   ret i32 %v0
 }
 ; CHECK-LABEL: cast_f2i
 ; CHECK: mov eax
-; CHECK: ret
 
 define internal float @cast_i2f(i32 %i) {
 entry:
   %v0 = bitcast i32 %i to float
   ret float %v0
 }
 ; CHECK-LABEL: cast_i2f
 ; CHECK: fld DWORD PTR
-; CHECK: ret
 
 define internal i64 @cast_d2ll(double %d) {
 entry:
   %v0 = bitcast double %d to i64
   ret i64 %v0
 }
 ; CHECK-LABEL: cast_d2ll
 ; CHECK: mov edx
-; CHECK: ret
 
 define internal i64 @cast_d2ll_const() {
 entry:
   %v0 = bitcast double 0x12345678901234 to i64
   ret i64 %v0
 }
 ; CHECK-LABEL: cast_d2ll_const
-; CHECK: movsd xmm{{.*}},QWORD PTR
-; CHECK: mov edx
-; CHECK: ret
+; CHECK: mov e{{..}},DWORD PTR ds:0x0 {{.*}} .L$double$0
+; CHECK: mov e{{..}},DWORD PTR ds:0x4 {{.*}} .L$double$0
 
 define internal double @cast_ll2d(i64 %ll) {
 entry:
   %v0 = bitcast i64 %ll to double
   ret double %v0
 }
 ; CHECK-LABEL: cast_ll2d
 ; CHECK: fld QWORD PTR
-; CHECK: ret
 
 define internal double @cast_ll2d_const() {
 entry:
   %v0 = bitcast i64 12345678901234 to double
   ret double %v0
 }
 ; CHECK-LABEL: cast_ll2d_const
 ; CHECK: mov {{.*}},0x73ce2ff2
 ; CHECK: mov {{.*}},0xb3a
 ; CHECK: fld QWORD PTR
-; CHECK: ret