From b19dd2bcaf219a3b5f144815c40b3f1b11a3d35d Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Tue, 2 Jul 2013 05:21:11 +0000 Subject: Revert r185257 (InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms) I'm reverting this commit because: 1. As discussed during review, it needs to be rewritten (to avoid creating and then deleting instructions). 2. This is causing optimizer crashes. Specifically, I'm seeing things like this: While deleting: i1 % Use still stuck around after Def is destroyed: = select i1 , i32 0, i32 1 opt: /src/llvm-trunk/lib/IR/Value.cpp:79: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed. I'd guess that these will go away once we're no longer creating/deleting instructions here, but just in case, I'm adding a regression test. Because the code is bring rewritten, I've just XFAIL'd the original regression test. Original commit message: InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms Real world code sometimes has the denominator of a 'udiv' be a 'select'. LLVM can handle such cases but only when the 'select' operands are symmetric in structure (both select operands are a constant power of two or a left shift, etc.). This falls apart if we are dealt a 'udiv' where the code is not symetric or if the select operands lead us to more select instructions. Instead, we should treat the LHS and each select operand as a distinct divide operation and try to optimize them independently. If we can to simplify each operation, then we can replace the 'udiv' with, say, a 'lshr' that has a new select with a bunch of new operands for the select. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185415 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Transforms/InstCombine/div-shift-crash.ll | 101 +++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 test/Transforms/InstCombine/div-shift-crash.ll (limited to 'test/Transforms/InstCombine/div-shift-crash.ll') diff --git a/test/Transforms/InstCombine/div-shift-crash.ll b/test/Transforms/InstCombine/div-shift-crash.ll new file mode 100644 index 0000000000..a619724564 --- /dev/null +++ b/test/Transforms/InstCombine/div-shift-crash.ll @@ -0,0 +1,101 @@ +; RUN: opt -instcombine < %s +target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64" +target triple = "powerpc64-unknown-linux-gnu" + +%struct.S0.0.1.2.3.4.13.22.31.44.48.53.54.55.56.58.59.60.66.68.70.74.77.106.107.108.109.110.113.117.118.128.129 = type <{ i64 }> + +; Function Attrs: nounwind +define void @main() #0 { +entry: + %l_819.i.i = alloca %struct.S0.0.1.2.3.4.13.22.31.44.48.53.54.55.56.58.59.60.66.68.70.74.77.106.107.108.109.110.113.117.118.128.129, align 8 + br i1 undef, label %land.lhs.true, label %for.cond.i + +land.lhs.true: ; preds = %entry + br label %for.cond.i + +for.cond.i: ; preds = %land.lhs.true, %entry + %0 = getelementptr inbounds %struct.S0.0.1.2.3.4.13.22.31.44.48.53.54.55.56.58.59.60.66.68.70.74.77.106.107.108.109.110.113.117.118.128.129* %l_819.i.i, i64 0, i32 0 + br label %for.cond.i6.i.i + +for.cond.i6.i.i: ; preds = %for.body.i8.i.i, %for.cond.i + br i1 undef, label %for.body.i8.i.i, label %lbl_707.i.i.i + +for.body.i8.i.i: ; preds = %for.cond.i6.i.i + br label %for.cond.i6.i.i + +lbl_707.i.i.i: ; preds = %for.cond.i6.i.i + br i1 undef, label %lor.rhs.i.i.i, label %lor.end.i.i.i + +lor.rhs.i.i.i: ; preds = %lbl_707.i.i.i + br label %lor.end.i.i.i + +lor.end.i.i.i: ; preds = %lor.rhs.i.i.i, %lbl_707.i.i.i + br label %for.cond1.i.i.i.i + +for.cond1.i.i.i.i: ; preds = %for.body4.i.i.i.i, %lor.end.i.i.i + br i1 undef, label %for.body4.i.i.i.i, label %func_39.exit.i.i + +for.body4.i.i.i.i: ; preds = %for.cond1.i.i.i.i + br label %for.cond1.i.i.i.i + +func_39.exit.i.i: ; preds = %for.cond1.i.i.i.i + %l_8191.sroa.0.0.copyload.i.i = load i64* %0, align 1 + br label %for.cond1.i.i.i + +for.cond1.i.i.i: ; preds = %safe_div_func_uint32_t_u_u.exit.i.i.i, %func_39.exit.i.i + br i1 undef, label %for.cond7.i.i.i, label %func_11.exit.i + +for.cond7.i.i.i: ; preds = %for.end30.i.i.i, %for.cond1.i.i.i + %storemerge.i.i.i = phi i32 [ %sub.i.i.i, %for.end30.i.i.i ], [ 4, %for.cond1.i.i.i ] + br i1 undef, label %for.cond22.i.i.i, label %for.end32.i.i.i + +for.cond22.i.i.i: ; preds = %for.body25.i.i.i, %for.cond7.i.i.i + br i1 undef, label %for.body25.i.i.i, label %for.end30.i.i.i + +for.body25.i.i.i: ; preds = %for.cond22.i.i.i + br label %for.cond22.i.i.i + +for.end30.i.i.i: ; preds = %for.cond22.i.i.i + %sub.i.i.i = add nsw i32 0, -1 + br label %for.cond7.i.i.i + +for.end32.i.i.i: ; preds = %for.cond7.i.i.i + %conv33.i.i.i = trunc i64 %l_8191.sroa.0.0.copyload.i.i to i32 + %xor.i.i.i.i = xor i32 %storemerge.i.i.i, -701565022 + %sub.i.i.i.i = sub nsw i32 0, %storemerge.i.i.i + %xor3.i.i.i.i = xor i32 %sub.i.i.i.i, %storemerge.i.i.i + %and4.i.i.i.i = and i32 %xor.i.i.i.i, %xor3.i.i.i.i + %cmp.i.i.i.i = icmp slt i32 %and4.i.i.i.i, 0 + %sub5.i.i.i.i = sub nsw i32 -701565022, %storemerge.i.i.i + %.sub5.i.i.i.i = select i1 %cmp.i.i.i.i, i32 -701565022, i32 %sub5.i.i.i.i + br i1 undef, label %safe_div_func_uint32_t_u_u.exit.i.i.i, label %cond.false.i.i.i.i + +cond.false.i.i.i.i: ; preds = %for.end32.i.i.i + %div.i.i.i.i = udiv i32 %conv33.i.i.i, %.sub5.i.i.i.i + br label %safe_div_func_uint32_t_u_u.exit.i.i.i + +safe_div_func_uint32_t_u_u.exit.i.i.i: ; preds = %cond.false.i.i.i.i, %for.end32.i.i.i + %cond.i.i.i.i = phi i32 [ %div.i.i.i.i, %cond.false.i.i.i.i ], [ %conv33.i.i.i, %for.end32.i.i.i ] + %cmp35.i.i.i = icmp ne i32 %cond.i.i.i.i, -7 + br label %for.cond1.i.i.i + +func_11.exit.i: ; preds = %for.cond1.i.i.i + br i1 undef, label %for.body, label %for.end + +for.body: ; preds = %func_11.exit.i + unreachable + +for.end: ; preds = %func_11.exit.i + br label %for.cond15 + +for.cond15: ; preds = %for.cond19, %for.end + br i1 undef, label %for.cond19, label %for.end45 + +for.cond19: ; preds = %for.cond15 + br label %for.cond15 + +for.end45: ; preds = %for.cond15 + unreachable +} + +attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" } -- cgit v1.2.3