x86 FP atomic codegen: don't drop globals, stack

Summary:
x86 codegen is clever about generating good code for relaxed
floating-point operations, but it was being silly when globals and
immediates were involved, forgetting where the global was and
loading/storing from/to the wrong place. The same applied to hard-coded
address immediates.

Don't let it forget about the displacement.

This fixes https://llvm.org/bugs/show_bug.cgi?id=25171

A very similar bug when doing floating-points atomics to the stack is
also fixed by this patch.

This fixes https://llvm.org/bugs/show_bug.cgi?id=25144

Reviewers: pete

Subscribers: llvm-commits, majnemer, rsmith

Differential Revision: http://reviews.llvm.org/D13749

llvm-svn: 250429

2 files changed, 118 insertions, 5 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 182e9116bfb..618290a257a 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -21105,21 +21105,26 @@ X86TargetLowering::EmitLoweredAtomicFP(MachineInstr *MI,
   const X86InstrInfo *TII = Subtarget->getInstrInfo();
   DebugLoc DL = MI->getDebugLoc();
   MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
-  unsigned MSrc = MI->getOperand(0).getReg();
+  MachineOperand MSrc = MI->getOperand(0);
   unsigned VSrc = MI->getOperand(5).getReg();
+  const MachineOperand &Disp = MI->getOperand(3);
+  MachineOperand ZeroDisp = MachineOperand::CreateImm(0);
+  bool hasDisp = Disp.isGlobal() || Disp.isImm();
+  if (hasDisp && MSrc.isReg())
+    MSrc.setIsKill(false);
   MachineInstrBuilder MIM = BuildMI(*BB, MI, DL, TII->get(MOp))
-                                .addReg(/*Base=*/MSrc)
+                                .addOperand(/*Base=*/MSrc)
                                 .addImm(/*Scale=*/1)
                                 .addReg(/*Index=*/0)
-                                .addImm(0)
+                                .addDisp(hasDisp ? Disp : ZeroDisp, /*off=*/0)
                                 .addReg(0);
   MachineInstr *MIO = BuildMI(*BB, (MachineInstr *)MIM, DL, TII->get(FOp),
                               MRI.createVirtualRegister(MRI.getRegClass(VSrc)))
                           .addReg(VSrc)
-                          .addReg(/*Base=*/MSrc)
+                          .addOperand(/*Base=*/MSrc)
                           .addImm(/*Scale=*/1)
                           .addReg(/*Index=*/0)
-                          .addImm(/*Disp=*/0)
+                          .addDisp(hasDisp ? Disp : ZeroDisp, /*off=*/0)
                           .addReg(/*Segment=*/0);
   MIM.addReg(MIO->getOperand(0).getReg(), RegState::Kill);
   MI->eraseFromParent(); // The pseudo instruction is gone now.
diff --git a/llvm/test/CodeGen/X86/atomic_mi.ll b/llvm/test/CodeGen/X86/atomic_mi.ll
index 7be79113620..356d9dcff6f 100644
--- a/llvm/test/CodeGen/X86/atomic_mi.ll
+++ b/llvm/test/CodeGen/X86/atomic_mi.ll
@@ -871,3 +871,111 @@ define void @fadd_64r(double* %loc, double %val) {
   store atomic i64 %3, i64* %floc release, align 8
   ret void
 }
+
+@glob32 = global float 0.000000e+00, align 4
+@glob64 = global double 0.000000e+00, align 8
+
+; Floating-point add to a global using an immediate.
+define void @fadd_32g() {
+; X64-LABEL: fadd_32g:
+; X64-NOT: lock
+; X64:      movss .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addss glob32(%rip), %[[XMM]]
+; X64-NEXT: movss %[[XMM]], glob32(%rip)
+; X32-LABEL: fadd_32g:
+; Don't check x86-32 (see comment above).
+  %i = load atomic i32, i32* bitcast (float* @glob32 to i32*) monotonic, align 4
+  %f = bitcast i32 %i to float
+  %add = fadd float %f, 1.000000e+00
+  %s = bitcast float %add to i32
+  store atomic i32 %s, i32* bitcast (float* @glob32 to i32*) monotonic, align 4
+  ret void
+}
+
+define void @fadd_64g() {
+; X64-LABEL: fadd_64g:
+; X64-NOT: lock
+; X64:      movsd .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addsd glob64(%rip), %[[XMM]]
+; X64-NEXT: movsd %[[XMM]], glob64(%rip)
+; X32-LABEL: fadd_64g:
+; Don't check x86-32 (see comment above).
+  %i = load atomic i64, i64* bitcast (double* @glob64 to i64*) monotonic, align 8
+  %f = bitcast i64 %i to double
+  %add = fadd double %f, 1.000000e+00
+  %s = bitcast double %add to i64
+  store atomic i64 %s, i64* bitcast (double* @glob64 to i64*) monotonic, align 8
+  ret void
+}
+
+; Floating-point add to a hard-coded immediate location using an immediate.
+define void @fadd_32imm() {
+; X64-LABEL: fadd_32imm:
+; X64-NOT: lock
+; X64:      movl $3735928559, %e[[M:[a-z]+]]
+; X64:      movss .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addss (%r[[M]]), %[[XMM]]
+; X64-NEXT: movss %[[XMM]], (%r[[M]])
+; X32-LABEL: fadd_32imm:
+; Don't check x86-32 (see comment above).
+  %i = load atomic i32, i32* inttoptr (i32 3735928559 to i32*) monotonic, align 4
+  %f = bitcast i32 %i to float
+  %add = fadd float %f, 1.000000e+00
+  %s = bitcast float %add to i32
+  store atomic i32 %s, i32* inttoptr (i32 3735928559 to i32*) monotonic, align 4
+  ret void
+}
+
+define void @fadd_64imm() {
+; X64-LABEL: fadd_64imm:
+; X64-NOT: lock
+; X64:      movl $3735928559, %e[[M:[a-z]+]]
+; X64:      movsd .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addsd (%r[[M]]), %[[XMM]]
+; X64-NEXT: movsd %[[XMM]], (%r[[M]])
+; X32-LABEL: fadd_64imm:
+; Don't check x86-32 (see comment above).
+  %i = load atomic i64, i64* inttoptr (i64 3735928559 to i64*) monotonic, align 8
+  %f = bitcast i64 %i to double
+  %add = fadd double %f, 1.000000e+00
+  %s = bitcast double %add to i64
+  store atomic i64 %s, i64* inttoptr (i64 3735928559 to i64*) monotonic, align 8
+  ret void
+}
+
+; Floating-point add to a stack location.
+define void @fadd_32stack() {
+; X64-LABEL: fadd_32stack:
+; X64-NOT: lock
+; X64:      movss .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addss [[STACKOFF:-?[0-9]+]](%rsp), %[[XMM]]
+; X64-NEXT: movss %[[XMM]], [[STACKOFF]](%rsp)
+; X32-LABEL: fadd_32stack:
+; Don't check x86-32 (see comment above).
+  %ptr = alloca i32, align 4
+  %bc3 = bitcast i32* %ptr to float*
+  %load = load atomic i32, i32* %ptr acquire, align 4
+  %bc0 = bitcast i32 %load to float
+  %fadd = fadd float 1.000000e+00, %bc0
+  %bc1 = bitcast float %fadd to i32
+  store atomic i32 %bc1, i32* %ptr release, align 4
+  ret void
+}
+
+define void @fadd_64stack() {
+; X64-LABEL: fadd_64stack:
+; X64-NOT: lock
+; X64:      movsd .{{[A-Z0-9_]+}}(%rip), %[[XMM:xmm[0-9]+]]
+; X64-NEXT: addsd [[STACKOFF:-?[0-9]+]](%rsp), %[[XMM]]
+; X64-NEXT: movsd %[[XMM]], [[STACKOFF]](%rsp)
+; X32-LABEL: fadd_64stack:
+; Don't check x86-32 (see comment above).
+  %ptr = alloca i64, align 8
+  %bc3 = bitcast i64* %ptr to double*
+  %load = load atomic i64, i64* %ptr acquire, align 8
+  %bc0 = bitcast i64 %load to double
+  %fadd = fadd double 1.000000e+00, %bc0
+  %bc1 = bitcast double %fadd to i64
+  store atomic i64 %bc1, i64* %ptr release, align 8
+  ret void
+}