[CodeGen] Round [SU]INT_TO_FP result when promoting from f16.

If we don't, values that aren't precisely representable in f16 could
be used as-is in a promoted f32 operation, which would produce
incorrect results.

AArch64 had the correct behavior; add a focused test.

Fixes http://llvm.org/PR26871

llvm-svn: 268700

4 files changed, 109 insertions, 5 deletions

diff --git a/llvm/test/CodeGen/AArch64/f16-instructions.ll b/llvm/test/CodeGen/AArch64/f16-instructions.ll
index 8ba4e363741..df26cefa328 100644
--- a/llvm/test/CodeGen/AArch64/f16-instructions.ll
+++ b/llvm/test/CodeGen/AArch64/f16-instructions.ll
@@ -446,6 +446,34 @@ define half @test_sitofp_i64(i64 %a) #0 {
   ret half %r
 }
 
+; CHECK-LABEL: test_uitofp_i32_fadd:
+; CHECK-NEXT: ucvtf s1, w0
+; CHECK-NEXT: fcvt h1, s1
+; CHECK-NEXT: fcvt s0, h0
+; CHECK-NEXT: fcvt s1, h1
+; CHECK-NEXT: fadd s0, s0, s1
+; CHECK-NEXT: fcvt h0, s0
+; CHECK-NEXT: ret
+define half @test_uitofp_i32_fadd(i32 %a, half %b) #0 {
+  %c = uitofp i32 %a to half
+  %r = fadd half %b, %c
+  ret half %r
+}
+
+; CHECK-LABEL: test_sitofp_i32_fadd:
+; CHECK-NEXT: scvtf s1, w0
+; CHECK-NEXT: fcvt h1, s1
+; CHECK-NEXT: fcvt s0, h0
+; CHECK-NEXT: fcvt s1, h1
+; CHECK-NEXT: fadd s0, s0, s1
+; CHECK-NEXT: fcvt h0, s0
+; CHECK-NEXT: ret
+define half @test_sitofp_i32_fadd(i32 %a, half %b) #0 {
+  %c = sitofp i32 %a to half
+  %r = fadd half %b, %c
+  ret half %r
+}
+
 ; CHECK-LABEL: test_fptrunc_float:
 ; CHECK-NEXT: fcvt h0, s0
 ; CHECK-NEXT: ret
diff --git a/llvm/test/CodeGen/ARM/fp16-promote.ll b/llvm/test/CodeGen/ARM/fp16-promote.ll
index 2a2eb8d2b6b..4da56b7ef35 100644
--- a/llvm/test/CodeGen/ARM/fp16-promote.ll
+++ b/llvm/test/CodeGen/ARM/fp16-promote.ll
@@ -889,4 +889,44 @@ define half @test_struct_arg(%struct.dummy %p) {
   ret half %a
 }
 
+; CHECK-LABEL: test_uitofp_i32_fadd:
+; CHECK-VFP-DAG: vcvt.f32.u32
+; CHECK-NOVFP-DAG: bl __aeabi_ui2f
+
+; CHECK-FP16-DAG: vcvtb.f16.f32
+; CHECK-FP16-DAG: vcvtb.f32.f16
+; CHECK-LIBCALL-DAG: bl __aeabi_h2f
+; CHECK-LIBCALL-DAG: bl __aeabi_h2f
+
+; CHECK-VFP-DAG: vadd.f32
+; CHECK-NOVFP-DAG: bl __aeabi_fadd
+
+; CHECK-FP16-DAG: vcvtb.f16.f32
+; CHECK-LIBCALL-DAG: bl __aeabi_f2h
+define half @test_uitofp_i32_fadd(i32 %a, half %b) #0 {
+  %c = uitofp i32 %a to half
+  %r = fadd half %b, %c
+  ret half %r
+}
+
+; CHECK-LABEL: test_sitofp_i32_fadd:
+; CHECK-VFP-DAG: vcvt.f32.s32
+; CHECK-NOVFP-DAG: bl __aeabi_i2f
+
+; CHECK-FP16-DAG: vcvtb.f16.f32
+; CHECK-FP16-DAG: vcvtb.f32.f16
+; CHECK-LIBCALL-DAG: bl __aeabi_h2f
+; CHECK-LIBCALL-DAG: bl __aeabi_h2f
+
+; CHECK-VFP-DAG: vadd.f32
+; CHECK-NOVFP-DAG: bl __aeabi_fadd
+
+; CHECK-FP16-DAG: vcvtb.f16.f32
+; CHECK-LIBCALL-DAG: bl __aeabi_f2h
+define half @test_sitofp_i32_fadd(i32 %a, half %b) #0 {
+  %c = sitofp i32 %a to half
+  %r = fadd half %b, %c
+  ret half %r
+}
+
 attributes #0 = { nounwind }
diff --git a/llvm/test/CodeGen/ARM/fp16-v3.ll b/llvm/test/CodeGen/ARM/fp16-v3.ll
index 4a120723542..e26455e61e7 100644
--- a/llvm/test/CodeGen/ARM/fp16-v3.ll
+++ b/llvm/test/CodeGen/ARM/fp16-v3.ll
@@ -4,11 +4,13 @@ target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
 target triple = "armv7a--none-eabi"
 
 ; CHECK-LABEL: test_vec3:
-; CHECK: vcvtb.f32.f16
-; CHECK: vcvt.f32.s32
-; CHECK: vadd.f32
-; CHECK-NEXT: vcvtb.f16.f32 [[SREG:s[0-9]+]], {{.*}}
-; CHECK-NEXT: vmov [[RREG1:r[0-9]+]], [[SREG]]
+; CHECK-DAG: vcvtb.f32.f16 [[SREG1:s[0-9]+]],
+; CHECK-DAG: vcvt.f32.s32 [[SREG2:s[0-9]+]],
+; CHECK-DAG: vcvtb.f16.f32 [[SREG3:s[0-9]+]], [[SREG2]]
+; CHECK-DAG: vcvtb.f32.f16 [[SREG4:s[0-9]+]], [[SREG3]]
+; CHECK: vadd.f32 [[SREG5:s[0-9]+]], [[SREG4]], [[SREG1]]
+; CHECK-NEXT: vcvtb.f16.f32 [[SREG6:s[0-9]+]], [[SREG5]]
+; CHECK-NEXT: vmov [[RREG1:r[0-9]+]], [[SREG6]]
 ; CHECK-NEXT: uxth [[RREG2:r[0-9]+]], [[RREG1]]
 ; CHECK-NEXT: pkhbt [[RREG3:r[0-9]+]], [[RREG1]], [[RREG1]], lsl #16
 ; CHECK-DAG: strh [[RREG1]], [r0, #4]
diff --git a/llvm/test/CodeGen/X86/half.ll b/llvm/test/CodeGen/X86/half.ll
index 9a9fb582055..717ddbfa6fd 100644
--- a/llvm/test/CodeGen/X86/half.ll
+++ b/llvm/test/CodeGen/X86/half.ll
@@ -279,4 +279,38 @@ define half @test_f80trunc_nodagcombine() #0 {
   ret half %2
 }
 
+; CHECK-LABEL: test_sitofp_fadd_i32:
+
+; CHECK-LIBCALL-NEXT: pushq %rbx
+; CHECK-LIBCALL-NEXT: subq $16, %rsp
+; CHECK-LIBCALL-NEXT: movl %edi, %ebx
+; CHECK-LIBCALL-NEXT: movzwl (%rsi), %edi
+; CHECK-LIBCALL-NEXT: callq __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT: movss %xmm0, 12(%rsp)
+; CHECK-LIBCALL-NEXT: cvtsi2ssl %ebx, %xmm0
+; CHECK-LIBCALL-NEXT: callq __gnu_f2h_ieee
+; CHECK-LIBCALL-NEXT: movzwl %ax, %edi
+; CHECK-LIBCALL-NEXT: callq __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT: addss 12(%rsp), %xmm0
+; CHECK-LIBCALL-NEXT: addq $16, %rsp
+; CHECK-LIBCALL-NEXT: popq %rbx
+; CHECK-LIBCALL-NEXT: retq
+
+; CHECK-F16C-NEXT: movswl (%rsi), %eax
+; CHECK-F16C-NEXT: vmovd %eax, %xmm0
+; CHECK-F16C-NEXT: vcvtph2ps %xmm0, %xmm0
+; CHECK-F16C-NEXT: vcvtsi2ssl %edi, %xmm0, %xmm1
+; CHECK-F16C-NEXT: vcvtps2ph $4, %xmm1, %xmm1
+; CHECK-F16C-NEXT: vcvtph2ps %xmm1, %xmm1
+; CHECK-F16C-NEXT: vaddss %xmm1, %xmm0, %xmm0
+; CHECK-F16C-NEXT: retq
+
+define float @test_sitofp_fadd_i32(i32 %a, half* %b) #0 {
+  %tmp0 = load half, half* %b
+  %tmp1 = sitofp i32 %a to half
+  %tmp2 = fadd half %tmp0, %tmp1
+  %tmp3 = fpext half %tmp2 to float
+  ret float %tmp3
+}
+
 attributes #0 = { nounwind }