[X86] Remove hasSideEffects=1 from the X87 pseudos with folded load.

This was done in r321424 to prevent scheduling from reordering things. But now that we model FPCW as a dependency, I don't think the same scheduling we were trying to prevent can occur.

llvm-svn: 354628

Author: topperc

llvm/lib/Target/X86/X86InstrFPStack.td

@@ -180,7 +180,6 @@ def _Fp80 : FpI_<(outs RFP80:$dst), (ins RFP80:$src1, RFP80:$src2), TwoArgFP,
 // These instructions cannot address 80-bit memory.
 multiclass FPBinary<SDNode OpNode, Format fp, string asmstring,
                     bit Forward = 1> {
-let mayLoad = 1, hasSideEffects = 1 in {
 // ST(0) = ST(0) + [mem]
 def _Fp32m  : FpIf32<(outs RFP32:$dst),
                      (ins RFP32:$src1, f32mem:$src2), OneArgFPRW,
@@ -217,8 +216,10 @@ def _Fp80m64: FpI_<(outs RFP80:$dst),
                         (OpNode RFP80:$src1, (f80 (extloadf64 addr:$src2)))),
                        (set RFP80:$dst,
                         (OpNode (f80 (extloadf64 addr:$src2)), RFP80:$src1)))]>;
+let mayLoad = 1 in
 def _F32m  : FPI<0xD8, fp, (outs), (ins f32mem:$src),
                  !strconcat("f", asmstring, "{s}\t$src")>;
+let mayLoad = 1 in
 def _F64m  : FPI<0xDC, fp, (outs), (ins f64mem:$src),
                  !strconcat("f", asmstring, "{l}\t$src")>;
 // ST(0) = ST(0) + [memint]
@@ -264,11 +265,12 @@ def _FpI32m80 : FpI_<(outs RFP80:$dst), (ins RFP80:$src1, i32mem:$src2),
                            (OpNode RFP80:$src1, (X86fild32 addr:$src2))),
                           (set RFP80:$dst,
                            (OpNode (X86fild32 addr:$src2), RFP80:$src1)))]>;
+let mayLoad = 1 in
 def _FI16m  : FPI<0xDE, fp, (outs), (ins i16mem:$src),
                   !strconcat("fi", asmstring, "{s}\t$src")>;
+let mayLoad = 1 in
 def _FI32m  : FPI<0xDA, fp, (outs), (ins i32mem:$src),
                   !strconcat("fi", asmstring, "{l}\t$src")>;
-} // mayLoad = 1, hasSideEffects = 1
 }
 
 let Defs = [FPSW], Uses = [FPCW] in {

llvm/test/CodeGen/X86/pr34080-2.ll

@@ -62,13 +62,13 @@ define void @computeJD(%struct.DateTime*) nounwind {
 ; CHECK-NEXT:    imull $60000, 24(%ebx), %ecx # imm = 0xEA60
 ; CHECK-NEXT:    addl %eax, %ecx
 ; CHECK-NEXT:    fldl 28(%ebx)
-; CHECK-NEXT:    fmuls {{\.LCPI.*}}
 ; CHECK-NEXT:    fnstcw {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
 ; CHECK-NEXT:    orl $3072, %eax # imm = 0xC00
 ; CHECK-NEXT:    movw %ax, {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    movl %ecx, %eax
 ; CHECK-NEXT:    sarl $31, %eax
+; CHECK-NEXT:    fmuls {{\.LCPI.*}}
 ; CHECK-NEXT:    fldcw {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    fistpll {{[0-9]+}}(%esp)
 ; CHECK-NEXT:    fldcw {{[0-9]+}}(%esp)