diff --git a/llvm/lib/Transforms/Scalar/GVNHoist.cpp b/llvm/lib/Transforms/Scalar/GVNHoist.cpp --- a/llvm/lib/Transforms/Scalar/GVNHoist.cpp +++ b/llvm/lib/Transforms/Scalar/GVNHoist.cpp @@ -620,6 +620,8 @@ auto it1 = ValueBBs.find(BB); if (it1 != ValueBBs.end()) { // Iterate in reverse order to keep lower ranked values on the top. + LLVM_DEBUG(dbgs() << "\nVisiting: " << BB->getName() + << " for pushing instructions on stack";); for (std::pair &VI : reverse(it1->second)) { // Get the value of instruction I LLVM_DEBUG(dbgs() << "\nPushing on stack: " << *VI.second); @@ -673,12 +675,12 @@ if (!Root) return; // Depth first walk on PDom tree to fill the CHIargs at each PDF. - RenameStackType RenameStack; for (auto Node : depth_first(Root)) { BasicBlock *BB = Node->getBlock(); if (!BB) continue; + RenameStackType RenameStack; // Collect all values in BB and push to stack. fillRenameStack(BB, ValueBBs, RenameStack); diff --git a/llvm/test/Transforms/GVNHoist/hoist-pr46874.ll b/llvm/test/Transforms/GVNHoist/hoist-pr46874.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/GVNHoist/hoist-pr46874.ll @@ -0,0 +1,65 @@ +; RUN: opt -gvn-hoist -S < %s | FileCheck %s +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@input = local_unnamed_addr global i32* null, align 8 + +; Check that the load instruction is **not** hoisted +; CHECK-LABEL: @_Z3fooPii +; CHECK-LABEL: if.then: +; CHECK-NEXT: load +; CHECK-LABEL: if2: +; CHECK: load +; CHECK-LABEL: @main + +define i32 @_Z3fooPii(i32* %p, i32 %x) local_unnamed_addr { +entry: + %cmp.not = icmp eq i32* %p, null + br i1 %cmp.not, label %if.end3, label %if.then + +if.then: ; preds = %entry + %0 = load i32, i32* %p, align 4, !tbaa !3 + %add = add nsw i32 %0, %x + %cmp1 = icmp eq i32 %add, 4 + br i1 %cmp1, label %if2, label %if.end3 + +if.end3: ; preds = %entry, %if.then + %x.addr.0 = phi i32 [ %add, %if.then ], [ %x, %entry ] + %add4 = add nsw i32 %x.addr.0, 2 + br i1 %cmp.not, label %if.end11, label %if2 + +if2: ; preds = %if.end3, %if.then + %x.addr.1 = phi i32 [ 4, %if.then ], [ %x.addr.0, %if.end3 ] + %y.0 = phi i32 [ 2, %if.then ], [ %add4, %if.end3 ] + %1 = load i32, i32* %p, align 4, !tbaa !3 + %add7 = add nsw i32 %x.addr.1, %1 + %cmp8 = icmp eq i32 %add7, 5 + br i1 %cmp8, label %end, label %if.end11 + +if.end11: ; preds = %if.end3, %if2 + %x.addr.2 = phi i32 [ %add7, %if2 ], [ %x.addr.0, %if.end3 ] + %y.1 = phi i32 [ %y.0, %if2 ], [ %add4, %if.end3 ] + %add12 = add nsw i32 %y.1, %x.addr.2 + br label %end + +end: ; preds = %if2, %if.end11 + %x.addr.3 = phi i32 [ 5, %if2 ], [ %x.addr.2, %if.end11 ] + %y.2 = phi i32 [ %y.0, %if2 ], [ %add12, %if.end11 ] + %add13 = add nsw i32 %x.addr.3, %y.2 + ret i32 %add13 +} + +define i32 @main() local_unnamed_addr { +entry: + %0 = load i32*, i32** @input, align 8, !tbaa !7 + %call = call i32 @_Z3fooPii(i32* %0, i32 0) + ret i32 %call +} + + +!3 = !{!4, !4, i64 0} +!4 = !{!"int", !5, i64 0} +!5 = !{!"omnipotent char", !6, i64 0} +!6 = !{!"Simple C++ TBAA"} +!7 = !{!8, !8, i64 0} +!8 = !{!"pointer@_ZTSPi", !5, i64 0} diff --git a/llvm/test/Transforms/GVNHoist/pr37445.ll b/llvm/test/Transforms/GVNHoist/pr37445.ll --- a/llvm/test/Transforms/GVNHoist/pr37445.ll +++ b/llvm/test/Transforms/GVNHoist/pr37445.ll @@ -1,8 +1,12 @@ ; RUN: opt < %s -early-cse-memssa -gvn-hoist -S | FileCheck %s ; Make sure opt won't crash and that this pair of -; instructions (load, icmp) is hoisted successfully -; from bb45 and bb58 to bb41. +; instructions (load, icmp) are not hoisted. +; Although it is safe to hoist the loads from bb45 to +; bb41, gvn-hoist does not have appropriate mechanism +; to handle corner cases (see PR46874) when these instructions +; were hoisted. +; FIXME: Hoist loads from bb58 and bb45 to bb41. @g_10 = external global i32, align 4 @g_536 = external global i8*, align 8 @@ -48,8 +52,6 @@ br label %bb12 ;CHECK: bb41: -;CHECK: %tmp47 = load i32, i32* %arg1, align 4 -;CHECK: %tmp48 = icmp eq i32 %tmp47, 0 bb41: %tmp43 = load i32, i32* %arg, align 4 @@ -57,8 +59,8 @@ br i1 %tmp44, label %bb52, label %bb45 ;CHECK: bb45: -;CHECK-NOT: %tmp47 = load i32, i32* %arg1, align 4 -;CHECK-NOT: %tmp48 = icmp eq i32 %tmp47, 0 +;CHECK: %tmp47 = load i32, i32* %arg1, align 4 +;CHECK: %tmp48 = icmp eq i32 %tmp47, 0 bb45: %tmp47 = load i32, i32* %arg1, align 4 @@ -78,9 +80,13 @@ %tmp57 = add nsw i32 %tmp8.0, 1 br label %bb52 -;CHECK: bb58: -;CHECK-NOT: %tmp60 = load i32, i32* %arg1, align 4 -;CHECK-NOT: %tmp61 = icmp eq i32 %tmp60, 0 +;CHECK: bb58: +;CHECK: %tmp60 = load i32, i32* %arg1, align 4 +;CHECK: %tmp61 = icmp eq i32 %tmp60, 0 +;CHECK: bb62: +;CHECK: load +;CHECK: bb64: +;CHECK: load bb58: %tmp60 = load i32, i32* %arg1, align 4