R600: Fix LowerSDIV24

Use ComputeNumSignBits instead of checking for i8 / i16 which only
worked when AMDIL was lying about having legal i8 / i16.

If an integer is known to fit in 24-bits, we can
do division faster with float ops.

llvm-svn: 213843

1 files changed, 120 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/R600/sdiv24.ll b/llvm/test/CodeGen/R600/sdiv24.ll
new file mode 100644
index 00000000000..84c9ecbbfda
--- /dev/null
+++ b/llvm/test/CodeGen/R600/sdiv24.ll
@@ -0,0 +1,120 @@
+; RUN: llc -march=r600 -mcpu=SI < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
+
+; FUNC-LABEL: @sdiv24_i8
+; SI: V_CVT_F32_I32
+; SI: V_CVT_F32_I32
+; SI: V_RCP_F32
+; SI: V_CVT_I32_F32
+
+; EG: INT_TO_FLT
+; EG-DAG: INT_TO_FLT
+; EG-DAG: RECIP_IEEE
+; EG: FLT_TO_INT
+define void @sdiv24_i8(i8 addrspace(1)* %out, i8 addrspace(1)* %in) {
+  %den_ptr = getelementptr i8 addrspace(1)* %in, i8 1
+  %num = load i8 addrspace(1) * %in
+  %den = load i8 addrspace(1) * %den_ptr
+  %result = sdiv i8 %num, %den
+  store i8 %result, i8 addrspace(1)* %out
+  ret void
+}
+
+; FUNC-LABEL: @sdiv24_i16
+; SI: V_CVT_F32_I32
+; SI: V_CVT_F32_I32
+; SI: V_RCP_F32
+; SI: V_CVT_I32_F32
+
+; EG: INT_TO_FLT
+; EG-DAG: INT_TO_FLT
+; EG-DAG: RECIP_IEEE
+; EG: FLT_TO_INT
+define void @sdiv24_i16(i16 addrspace(1)* %out, i16 addrspace(1)* %in) {
+  %den_ptr = getelementptr i16 addrspace(1)* %in, i16 1
+  %num = load i16 addrspace(1) * %in, align 2
+  %den = load i16 addrspace(1) * %den_ptr, align 2
+  %result = sdiv i16 %num, %den
+  store i16 %result, i16 addrspace(1)* %out, align 2
+  ret void
+}
+
+; FUNC-LABEL: @sdiv24_i32
+; SI: V_CVT_F32_I32
+; SI: V_CVT_F32_I32
+; SI: V_RCP_F32
+; SI: V_CVT_I32_F32
+
+; EG: INT_TO_FLT
+; EG-DAG: INT_TO_FLT
+; EG-DAG: RECIP_IEEE
+; EG: FLT_TO_INT
+define void @sdiv24_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
+  %den_ptr = getelementptr i32 addrspace(1)* %in, i32 1
+  %num = load i32 addrspace(1) * %in, align 4
+  %den = load i32 addrspace(1) * %den_ptr, align 4
+  %num.i24.0 = shl i32 %num, 8
+  %den.i24.0 = shl i32 %den, 8
+  %num.i24 = ashr i32 %num.i24.0, 8
+  %den.i24 = ashr i32 %den.i24.0, 8
+  %result = sdiv i32 %num.i24, %den.i24
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @sdiv25_i32
+; SI-NOT: V_CVT_F32_I32
+; SI-NOT: V_RCP_F32
+
+; EG-NOT: INT_TO_FLT
+; EG-NOT: RECIP_IEEE
+define void @sdiv25_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
+  %den_ptr = getelementptr i32 addrspace(1)* %in, i32 1
+  %num = load i32 addrspace(1) * %in, align 4
+  %den = load i32 addrspace(1) * %den_ptr, align 4
+  %num.i24.0 = shl i32 %num, 7
+  %den.i24.0 = shl i32 %den, 7
+  %num.i24 = ashr i32 %num.i24.0, 7
+  %den.i24 = ashr i32 %den.i24.0, 7
+  %result = sdiv i32 %num.i24, %den.i24
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @test_no_sdiv24_i32_1
+; SI-NOT: V_CVT_F32_I32
+; SI-NOT: V_RCP_F32
+
+; EG-NOT: INT_TO_FLT
+; EG-NOT: RECIP_IEEE
+define void @test_no_sdiv24_i32_1(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
+  %den_ptr = getelementptr i32 addrspace(1)* %in, i32 1
+  %num = load i32 addrspace(1) * %in, align 4
+  %den = load i32 addrspace(1) * %den_ptr, align 4
+  %num.i24.0 = shl i32 %num, 8
+  %den.i24.0 = shl i32 %den, 7
+  %num.i24 = ashr i32 %num.i24.0, 8
+  %den.i24 = ashr i32 %den.i24.0, 7
+  %result = sdiv i32 %num.i24, %den.i24
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @test_no_sdiv24_i32_2
+; SI-NOT: V_CVT_F32_I32
+; SI-NOT: V_RCP_F32
+
+; EG-NOT: INT_TO_FLT
+; EG-NOT: RECIP_IEEE
+define void @test_no_sdiv24_i32_2(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
+  %den_ptr = getelementptr i32 addrspace(1)* %in, i32 1
+  %num = load i32 addrspace(1) * %in, align 4
+  %den = load i32 addrspace(1) * %den_ptr, align 4
+  %num.i24.0 = shl i32 %num, 7
+  %den.i24.0 = shl i32 %den, 8
+  %num.i24 = ashr i32 %num.i24.0, 7
+  %den.i24 = ashr i32 %den.i24.0, 8
+  %result = sdiv i32 %num.i24, %den.i24
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}