From 0feb977bbfb0d6bb2c8d3178246acb035a739f37 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand Date: Mon, 4 Aug 2014 18:41:00 +0200 Subject: [PATCH] gallivm: Fix Altivec pack intrinsics for little-endian This patch fixes use of Altivec pack intrinsics on little-endian PowerPC systems. Since little-endian operation only affects the load and store instructions, the semantics of pack (and other) instructions that take two input vectors implicitly change: the pack instructions still fill a register placing values from the first operand into the "high" parts of the register, and values from the second operand into the "low" parts of the register, but since vector loads and stores perform an endian swap, the high parts end up at high memory addresses. To still achieve the desired effect, we have to swap the two inputs to the pack instruction on little-endian systems. This is done automatically by the back-end for instructions generated by LLVM, but needs to be done manually when emitting intrisincs (which still result in that instruction being emitted directly). Signed-off-by: Ulrich Weigand Signed-off-by: Maarten Lankhorst --- src/gallium/auxiliary/gallivm/lp_bld_pack.c | 26 +++++++++++++++++---- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_pack.c b/src/gallium/auxiliary/gallivm/lp_bld_pack.c index a48a9225eb2..cdf6d80c261 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_pack.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_pack.c @@ -464,6 +464,7 @@ lp_build_pack2(struct gallivm_state *gallivm, if((util_cpu_caps.has_sse2 || util_cpu_caps.has_altivec) && src_type.width * src_type.length >= 128) { const char *intrinsic = NULL; + boolean swap_intrinsic_operands = FALSE; switch(src_type.width) { case 32: @@ -482,6 +483,9 @@ lp_build_pack2(struct gallivm_state *gallivm, } else { intrinsic = "llvm.ppc.altivec.vpkuwus"; } +#ifdef PIPE_ARCH_LITTLE_ENDIAN + swap_intrinsic_operands = TRUE; +#endif } break; case 16: @@ -490,12 +494,18 @@ lp_build_pack2(struct gallivm_state *gallivm, intrinsic = "llvm.x86.sse2.packsswb.128"; } else if (util_cpu_caps.has_altivec) { intrinsic = "llvm.ppc.altivec.vpkshss"; +#ifdef PIPE_ARCH_LITTLE_ENDIAN + swap_intrinsic_operands = TRUE; +#endif } } else { if (util_cpu_caps.has_sse2) { intrinsic = "llvm.x86.sse2.packuswb.128"; } else if (util_cpu_caps.has_altivec) { intrinsic = "llvm.ppc.altivec.vpkshus"; +#ifdef PIPE_ARCH_LITTLE_ENDIAN + swap_intrinsic_operands = TRUE; +#endif } } break; @@ -504,7 +514,11 @@ lp_build_pack2(struct gallivm_state *gallivm, if (intrinsic) { if (src_type.width * src_type.length == 128) { LLVMTypeRef intr_vec_type = lp_build_vec_type(gallivm, intr_type); - res = lp_build_intrinsic_binary(builder, intrinsic, intr_vec_type, lo, hi); + if (swap_intrinsic_operands) { + res = lp_build_intrinsic_binary(builder, intrinsic, intr_vec_type, hi, lo); + } else { + res = lp_build_intrinsic_binary(builder, intrinsic, intr_vec_type, lo, hi); + } if (dst_vec_type != intr_vec_type) { res = LLVMBuildBitCast(builder, res, dst_vec_type, ""); } @@ -513,6 +527,8 @@ lp_build_pack2(struct gallivm_state *gallivm, int num_split = src_type.width * src_type.length / 128; int i; int nlen = 128 / src_type.width; + int lo_off = swap_intrinsic_operands ? nlen : 0; + int hi_off = swap_intrinsic_operands ? 0 : nlen; struct lp_type ndst_type = lp_type_unorm(dst_type.width, 128); struct lp_type nintr_type = lp_type_unorm(intr_type.width, 128); LLVMValueRef tmpres[LP_MAX_VECTOR_WIDTH / 128]; @@ -524,9 +540,9 @@ lp_build_pack2(struct gallivm_state *gallivm, for (i = 0; i < num_split / 2; i++) { tmplo = lp_build_extract_range(gallivm, - lo, i*nlen*2, nlen); + lo, i*nlen*2 + lo_off, nlen); tmphi = lp_build_extract_range(gallivm, - lo, i*nlen*2 + nlen, nlen); + lo, i*nlen*2 + hi_off, nlen); tmpres[i] = lp_build_intrinsic_binary(builder, intrinsic, nintr_vec_type, tmplo, tmphi); if (ndst_vec_type != nintr_vec_type) { @@ -535,9 +551,9 @@ lp_build_pack2(struct gallivm_state *gallivm, } for (i = 0; i < num_split / 2; i++) { tmplo = lp_build_extract_range(gallivm, - hi, i*nlen*2, nlen); + hi, i*nlen*2 + lo_off, nlen); tmphi = lp_build_extract_range(gallivm, - hi, i*nlen*2 + nlen, nlen); + hi, i*nlen*2 + hi_off, nlen); tmpres[i+num_split/2] = lp_build_intrinsic_binary(builder, intrinsic, nintr_vec_type, tmplo, tmphi); -- 2.30.2