From 9922ea7e669f0df13eff1594cd1799038d9c95ab Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 26 Nov 2020 06:16:39 +1000 Subject: [PATCH] gallivm: fix idiv/irem for 8/16/64-bit and 32-bit INT_MIN/-1 This fixes integer division for non-32bit but also fixes the 32-bit case where INT_MIN/-1 causes an exception. Fixes CL CTS ./integer_ops/test_integer_ops quick_long_math Reviewed-by: Roland Scheidegger Part-of: --- src/gallium/auxiliary/gallivm/lp_bld_nir.c | 56 ++++++++++++++++++++++++++---- 1 file changed, 49 insertions(+), 7 deletions(-) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir.c b/src/gallium/auxiliary/gallivm/lp_bld_nir.c index 5884f0a..d9ccc5a 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_nir.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_nir.c @@ -448,6 +448,43 @@ merge_16bit(struct lp_build_nir_context *bld_base, return LLVMBuildShuffleVector(builder, input, input2, LLVMConstVector(shuffles, len), ""); } +static LLVMValueRef get_signed_divisor(struct gallivm_state *gallivm, + struct lp_build_context *int_bld, + struct lp_build_context *mask_bld, + int src_bit_size, + LLVMValueRef src, LLVMValueRef divisor) +{ + LLVMBuilderRef builder = gallivm->builder; + /* However for signed divides SIGFPE can occur if the numerator is INT_MIN + and divisor is -1. */ + /* set mask if numerator == INT_MIN */ + long long min_val; + switch (src_bit_size) { + case 8: + min_val = INT8_MIN; + break; + case 16: + min_val = INT16_MIN; + break; + default: + case 32: + min_val = INT_MIN; + break; + case 64: + min_val = INT64_MIN; + break; + } + LLVMValueRef div_mask2 = lp_build_cmp(mask_bld, PIPE_FUNC_EQUAL, src, + lp_build_const_int_vec(gallivm, int_bld->type, min_val)); + /* set another mask if divisor is - 1 */ + LLVMValueRef div_mask3 = lp_build_cmp(mask_bld, PIPE_FUNC_EQUAL, divisor, + lp_build_const_int_vec(gallivm, int_bld->type, -1)); + div_mask2 = LLVMBuildAnd(builder, div_mask2, div_mask3, ""); + + divisor = lp_build_select(mask_bld, div_mask2, int_bld->one, divisor); + return divisor; +} + static LLVMValueRef do_int_divide(struct lp_build_nir_context *bld_base, bool is_unsigned, unsigned src_bit_size, @@ -457,16 +494,16 @@ do_int_divide(struct lp_build_nir_context *bld_base, LLVMBuilderRef builder = gallivm->builder; struct lp_build_context *int_bld = get_int_bld(bld_base, is_unsigned, src_bit_size); struct lp_build_context *mask_bld = get_int_bld(bld_base, true, src_bit_size); + + /* avoid divide by 0. Converted divisor from 0 to -1 */ LLVMValueRef div_mask = lp_build_cmp(mask_bld, PIPE_FUNC_EQUAL, src2, mask_bld->zero); + LLVMValueRef divisor = LLVMBuildOr(builder, div_mask, src2, ""); if (!is_unsigned) { - /* INT_MIN (0x80000000) / -1 (0xffffffff) causes sigfpe, seen with blender. */ - div_mask = LLVMBuildAnd(builder, div_mask, lp_build_const_int_vec(gallivm, int_bld->type, 0x7fffffff), ""); + divisor = get_signed_divisor(gallivm, int_bld, mask_bld, + src_bit_size, src, divisor); } - LLVMValueRef divisor = LLVMBuildOr(builder, - div_mask, - src2, ""); LLVMValueRef result = lp_build_div(int_bld, src, divisor); if (!is_unsigned) { @@ -486,11 +523,16 @@ do_int_mod(struct lp_build_nir_context *bld_base, struct gallivm_state *gallivm = bld_base->base.gallivm; LLVMBuilderRef builder = gallivm->builder; struct lp_build_context *int_bld = get_int_bld(bld_base, is_unsigned, src_bit_size); - LLVMValueRef div_mask = lp_build_cmp(int_bld, PIPE_FUNC_EQUAL, src2, - int_bld->zero); + struct lp_build_context *mask_bld = get_int_bld(bld_base, true, src_bit_size); + LLVMValueRef div_mask = lp_build_cmp(mask_bld, PIPE_FUNC_EQUAL, src2, + mask_bld->zero); LLVMValueRef divisor = LLVMBuildOr(builder, div_mask, src2, ""); + if (!is_unsigned) { + divisor = get_signed_divisor(gallivm, int_bld, mask_bld, + src_bit_size, src, divisor); + } LLVMValueRef result = lp_build_mod(int_bld, src, divisor); return LLVMBuildOr(builder, div_mask, result, ""); } -- 2.7.4