Index: llvm/lib/Transforms/Scalar/GVN.cpp =================================================================== --- llvm/lib/Transforms/Scalar/GVN.cpp +++ llvm/lib/Transforms/Scalar/GVN.cpp @@ -1673,8 +1673,9 @@ if (!isLoadInLoopPREEnabled() && LI && LI->getLoopFor(Load->getParent())) return Changed; - return Changed || PerformLoadPRE(Load, ValuesPerBlock, UnavailableBlocks) || - performLoopLoadPRE(Load, ValuesPerBlock, UnavailableBlocks); + return Changed || + performLoopLoadPRE(Load, ValuesPerBlock, UnavailableBlocks) || + PerformLoadPRE(Load, ValuesPerBlock, UnavailableBlocks); } static bool impliesEquivalanceIfTrue(CmpInst* Cmp) { Index: llvm/test/Transforms/GVN/gvn-loop-load-pre-order.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/GVN/gvn-loop-load-pre-order.ll @@ -0,0 +1,65 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -loops -gvn -S | FileCheck -check-prefix=CHECK-PRE %s +; RUN: opt < %s -loops -gvn -sccp -S | FileCheck -check-prefix=CHECK-SCCP %s + +@b = external global i32, align 4 + +define void @main(i1 %cond) { +; CHECK-PRE-LABEL: @main( +; CHECK-PRE-NEXT: entry: +; CHECK-PRE-NEXT: store i32 0, i32* @b, align 4 +; CHECK-PRE-NEXT: br label [[WHILE_BODY3:%.*]] +; CHECK-PRE: while.cond.loopexit.loopexit: +; CHECK-PRE-NEXT: ret void +; CHECK-PRE: while.body3: +; CHECK-PRE-NEXT: [[TMP0:%.*]] = phi i32 [ [[TMP1:%.*]], [[IF_END:%.*]] ], [ 0, [[ENTRY:%.*]] ] +; CHECK-PRE-NEXT: [[TOBOOL4_NOT:%.*]] = icmp eq i32 [[TMP0]], 0 +; CHECK-PRE-NEXT: br i1 [[TOBOOL4_NOT]], label [[IF_END]], label [[IF_THEN:%.*]] +; CHECK-PRE: if.then: +; CHECK-PRE-NEXT: tail call void @foo() +; CHECK-PRE-NEXT: [[DOTPRE:%.*]] = load i32, i32* @b, align 4 +; CHECK-PRE-NEXT: br label [[IF_END]] +; CHECK-PRE: if.end: +; CHECK-PRE-NEXT: [[TMP1]] = phi i32 [ [[DOTPRE]], [[IF_THEN]] ], [ 0, [[WHILE_BODY3]] ] +; CHECK-PRE-NEXT: br i1 [[COND:%.*]], label [[WHILE_COND_LOOPEXIT_LOOPEXIT:%.*]], label [[WHILE_BODY3]] +; +; CHECK-SCCP-LABEL: @main( +; CHECK-SCCP-NEXT: entry: +; CHECK-SCCP-NEXT: store i32 0, i32* @b, align 4 +; CHECK-SCCP-NEXT: br label [[WHILE_BODY3:%.*]] +; CHECK-SCCP: while.cond.loopexit.loopexit: +; CHECK-SCCP-NEXT: ret void +; CHECK-SCCP: while.body3: +; CHECK-SCCP-NEXT: br i1 true, label [[IF_END:%.*]], label [[IF_THEN:%.*]] +; CHECK-SCCP: if.then: +; CHECK-SCCP-NEXT: br label [[IF_END]] +; CHECK-SCCP: if.end: +; CHECK-SCCP-NEXT: br i1 [[COND:%.*]], label [[WHILE_COND_LOOPEXIT_LOOPEXIT:%.*]], label [[WHILE_BODY3]] +; +entry: + store i32 0, i32* @b + br label %while.body3.lr.ph + +while.cond.loopexit.loopexit: ; preds = %if.end + ret void + +while.body3.lr.ph: ; preds = %while.cond1.preheader + %0 = load i32, i32* @b, align 4 + %1 = icmp eq i32 %0, 0 + br label %while.body3 + +while.body3: ; preds = %if.end, %while.body3.lr.ph + %2 = load i32, i32* @b, align 4 + %tobool4.not = icmp eq i32 %2, 0 + br i1 %tobool4.not, label %if.end, label %if.then + +if.then: ; preds = %while.body3 + tail call void @foo() + br label %if.end + +if.end: ; preds = %if.then, %while.body3 + br i1 %cond, label %while.cond.loopexit.loopexit, label %while.body3 +} + +declare void @foo() +