llvm-6502/test/CodeGen/R600/sgpr-control-flow.ll
Matt Arsenault ec0a7cd15a R600/SI: Remove i1 pseudo VALU ops
Select i1 logical ops directly to 64-bit SALU instructions.
Vector i1 values are always really in SGPRs, with each
bit for each item in the wave. This saves about 4 instructions
when and/or/xoring any condition, and also helps write conditions
that need to be passed in vcc.

This should work correctly now that the SGPR live range
fixing pass works. More work is needed to eliminate the VReg_1
pseudo regclass and possibly the entire SILowerI1Copies pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223206 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-03 05:22:35 +00:00

106 lines
2.9 KiB
LLVM

; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs< %s | FileCheck -check-prefix=SI %s
;
;
; Most SALU instructions ignore control flow, so we need to make sure
; they don't overwrite values from other blocks.
; If the branch decision is made based on a value in an SGPR then all
; threads will execute the same code paths, so we don't need to worry
; about instructions in different blocks overwriting each other.
; SI-LABEL: {{^}}sgpr_if_else_salu_br:
; SI: s_add
; SI: s_add
define void @sgpr_if_else_salu_br(i32 addrspace(1)* %out, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
entry:
%0 = icmp eq i32 %a, 0
br i1 %0, label %if, label %else
if:
%1 = add i32 %b, %c
br label %endif
else:
%2 = add i32 %d, %e
br label %endif
endif:
%3 = phi i32 [%1, %if], [%2, %else]
%4 = add i32 %3, %a
store i32 %4, i32 addrspace(1)* %out
ret void
}
; The two S_ADD instructions should write to different registers, since
; different threads will take different control flow paths.
; SI-LABEL: {{^}}sgpr_if_else_valu_br:
; SI: s_add_i32 [[SGPR:s[0-9]+]]
; SI-NOT: s_add_i32 [[SGPR]]
define void @sgpr_if_else_valu_br(i32 addrspace(1)* %out, float %a, i32 %b, i32 %c, i32 %d, i32 %e) {
entry:
%tid = call i32 @llvm.r600.read.tidig.x() #0
%tid_f = uitofp i32 %tid to float
%tmp1 = fcmp ueq float %tid_f, 0.0
br i1 %tmp1, label %if, label %else
if:
%tmp2 = add i32 %b, %c
br label %endif
else:
%tmp3 = add i32 %d, %e
br label %endif
endif:
%tmp4 = phi i32 [%tmp2, %if], [%tmp3, %else]
store i32 %tmp4, i32 addrspace(1)* %out
ret void
}
; FIXME: Should write to different SGPR pairs instead of copying to
; VALU for i1 phi.
; SI-LABEL: {{^}}sgpr_if_else_valu_cmp_phi_br:
; SI: buffer_load_dword [[AVAL:v[0-9]+]]
; SI: v_cmp_lt_i32_e64 [[CMP_IF:s\[[0-9]+:[0-9]+\]]], [[AVAL]], 0
; SI: v_cndmask_b32_e64 [[V_CMP:v[0-9]+]], 0, -1, [[CMP_IF]]
; SI: BB2_1:
; SI: buffer_load_dword [[AVAL:v[0-9]+]]
; SI: v_cmp_eq_i32_e64 [[CMP_ELSE:s\[[0-9]+:[0-9]+\]]], [[AVAL]], 0
; SI: v_cndmask_b32_e64 [[V_CMP]], 0, -1, [[CMP_ELSE]]
; SI: v_cmp_ne_i32_e64 [[CMP_CMP:s\[[0-9]+:[0-9]+\]]], [[V_CMP]], 0
; SI: v_cndmask_b32_e64 [[RESULT:v[0-9]+]], 0, -1, [[CMP_CMP]]
; SI: buffer_store_dword [[RESULT]]
define void @sgpr_if_else_valu_cmp_phi_br(i32 addrspace(1)* %out, i32 addrspace(1)* %a, i32 addrspace(1)* %b) {
entry:
%tid = call i32 @llvm.r600.read.tidig.x() #0
%tmp1 = icmp eq i32 %tid, 0
br i1 %tmp1, label %if, label %else
if:
%gep.if = getelementptr i32 addrspace(1)* %a, i32 %tid
%a.val = load i32 addrspace(1)* %gep.if
%cmp.if = icmp eq i32 %a.val, 0
br label %endif
else:
%gep.else = getelementptr i32 addrspace(1)* %b, i32 %tid
%b.val = load i32 addrspace(1)* %gep.else
%cmp.else = icmp slt i32 %b.val, 0
br label %endif
endif:
%tmp4 = phi i1 [%cmp.if, %if], [%cmp.else, %else]
%ext = sext i1 %tmp4 to i32
store i32 %ext, i32 addrspace(1)* %out
ret void
}
declare i32 @llvm.r600.read.tidig.x() #0
attributes #0 = { readnone }