diff options
Diffstat (limited to 'dynamic-layers/clang-layer/recipes-devtools/clang/files/IndVarSimplify-Do-not-use-SCEV-expander-for-IVCount-.patch')
| -rw-r--r-- | dynamic-layers/clang-layer/recipes-devtools/clang/files/IndVarSimplify-Do-not-use-SCEV-expander-for-IVCount-.patch | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/dynamic-layers/clang-layer/recipes-devtools/clang/files/IndVarSimplify-Do-not-use-SCEV-expander-for-IVCount-.patch b/dynamic-layers/clang-layer/recipes-devtools/clang/files/IndVarSimplify-Do-not-use-SCEV-expander-for-IVCount-.patch new file mode 100644 index 00000000..48307deb --- /dev/null +++ b/dynamic-layers/clang-layer/recipes-devtools/clang/files/IndVarSimplify-Do-not-use-SCEV-expander-for-IVCount-.patch @@ -0,0 +1,146 @@ +From 35e218a886f4c066eabd18685240d55270bd5a6d Mon Sep 17 00:00:00 2001 +From: Aleksander Us <aleksander.us@intel.com> +Date: Mon, 26 Aug 2019 15:45:47 +0300 +Subject: [PATCH] [IndVarSimplify] Do not use SCEV expander for IVCount in + LFTR when possible. + +SCEV analysis cannot properly cache instruction with poison flags +(for example, add nsw outside of loop will not be reused by expander). +This can lead to generating of additional instructions by SCEV expander. + +Example IR: + + ... + %maxval = add nuw nsw i32 %a1, %a2 + ... +for.body: + ... + %cmp22 = icmp ult i32 %ivadd, %maxval + br i1 %cmp22, label %for.body, label %for.end + ... + +SCEV expander will generate copy of %maxval in preheader but without +nuw/nsw flags. This can be avoided by explicit check that iv count +value gives the same SCEV expressions as calculated by LFTR. + +Upstream-Status: Submitted [https://reviews.llvm.org/D66890] + +https://github.com/intel/llvm-patches/commit/fd6a6c97341a56fd21bc32bc940afea751312e8f + +Signed-off-by: Naveen Saini <naveen.kumar.saini@intel.com> +--- + lib/Transforms/Scalar/IndVarSimplify.cpp | 12 +++++++++- + test/Transforms/IndVarSimplify/add_nsw.ll | 23 ++++++++++++++++++++ + test/Transforms/IndVarSimplify/lftr-reuse.ll | 9 +++----- + test/Transforms/IndVarSimplify/udiv.ll | 1 + + 4 files changed, 38 insertions(+), 7 deletions(-) + create mode 100644 test/Transforms/IndVarSimplify/add_nsw.ll + +diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp +index f9fc698a4a9..5e04dac8aa6 100644 +--- a/lib/Transforms/Scalar/IndVarSimplify.cpp ++++ b/lib/Transforms/Scalar/IndVarSimplify.cpp +@@ -2375,6 +2375,17 @@ static Value *genLoopLimit(PHINode *IndVar, BasicBlock *ExitingBB, + if (UsePostInc) + IVLimit = SE->getAddExpr(IVLimit, SE->getOne(IVLimit->getType())); + ++ // If computed limit is equal to old limit then do not use SCEV expander ++ // because it can lost NUW/NSW flags and create extra instructions. ++ BranchInst *BI = cast<BranchInst>(ExitingBB->getTerminator()); ++ if (ICmpInst *Cmp = dyn_cast<ICmpInst>(BI->getOperand(0))) { ++ Value *Limit = Cmp->getOperand(0); ++ if (!L->isLoopInvariant(Limit)) ++ Limit = Cmp->getOperand(1); ++ if (SE->getSCEV(Limit) == IVLimit) ++ return Limit; ++ } ++ + // Expand the code for the iteration count. + assert(SE->isLoopInvariant(IVLimit, L) && + "Computed iteration count is not loop invariant!"); +@@ -2383,7 +2394,6 @@ static Value *genLoopLimit(PHINode *IndVar, BasicBlock *ExitingBB, + // SCEV expression (IVInit) for a pointer type IV value (IndVar). + Type *LimitTy = ExitCount->getType()->isPointerTy() ? + IndVar->getType() : ExitCount->getType(); +- BranchInst *BI = cast<BranchInst>(ExitingBB->getTerminator()); + return Rewriter.expandCodeFor(IVLimit, LimitTy, BI); + } + } +diff --git a/test/Transforms/IndVarSimplify/add_nsw.ll b/test/Transforms/IndVarSimplify/add_nsw.ll +new file mode 100644 +index 00000000000..abd1cbb6c51 +--- /dev/null ++++ b/test/Transforms/IndVarSimplify/add_nsw.ll +@@ -0,0 +1,23 @@ ++; RUN: opt -indvars -S %s | FileCheck %s ++ ++target datalayout = "e-p:32:32-i64:64-n8:16:32" ++ ++; CHECK: for.body.preheader: ++; CHECK-NOT: add ++; CHECK: for.body: ++ ++define void @foo(i32 %a1, i32 %a2) { ++entry: ++ %maxval = add nuw nsw i32 %a1, %a2 ++ %cmp = icmp slt i32 %maxval, 1 ++ br i1 %cmp, label %for.end, label %for.body ++ ++for.body: ; preds = %entry, %for.body ++ %j.02 = phi i32 [ 0, %entry ], [ %add31, %for.body ] ++ %add31 = add nuw nsw i32 %j.02, 1 ++ %cmp22 = icmp slt i32 %add31, %maxval ++ br i1 %cmp22, label %for.body, label %for.end ++ ++for.end: ; preds = %for.body ++ ret void ++} +diff --git a/test/Transforms/IndVarSimplify/lftr-reuse.ll b/test/Transforms/IndVarSimplify/lftr-reuse.ll +index 14ae9738696..509d662b767 100644 +--- a/test/Transforms/IndVarSimplify/lftr-reuse.ll ++++ b/test/Transforms/IndVarSimplify/lftr-reuse.ll +@@ -67,11 +67,9 @@ define void @expandOuterRecurrence(i32 %arg) nounwind { + ; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 0, [[SUB1]] + ; CHECK-NEXT: br i1 [[CMP1]], label [[OUTER_PREHEADER:%.*]], label [[EXIT:%.*]] + ; CHECK: outer.preheader: +-; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[ARG]], -1 + ; CHECK-NEXT: br label [[OUTER:%.*]] + ; CHECK: outer: +-; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i32 [ [[TMP0]], [[OUTER_PREHEADER]] ], [ [[INDVARS_IV_NEXT:%.*]], [[OUTER_INC:%.*]] ] +-; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_INC:%.*]], [[OUTER_INC]] ], [ 0, [[OUTER_PREHEADER]] ] ++; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_INC:%.*]], [[OUTER_INC:%.*]] ], [ 0, [[OUTER_PREHEADER]] ] + ; CHECK-NEXT: [[SUB2:%.*]] = sub nsw i32 [[ARG]], [[I]] + ; CHECK-NEXT: [[SUB3:%.*]] = sub nsw i32 [[SUB2]], 1 + ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 0, [[SUB3]] +@@ -81,14 +79,13 @@ define void @expandOuterRecurrence(i32 %arg) nounwind { + ; CHECK: inner: + ; CHECK-NEXT: [[J:%.*]] = phi i32 [ 0, [[INNER_PH]] ], [ [[J_INC:%.*]], [[INNER]] ] + ; CHECK-NEXT: [[J_INC]] = add nuw nsw i32 [[J]], 1 +-; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[J_INC]], [[INDVARS_IV]] ++; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[J_INC]], [[SUB3]] + ; CHECK-NEXT: br i1 [[EXITCOND]], label [[INNER]], label [[OUTER_INC_LOOPEXIT:%.*]] + ; CHECK: outer.inc.loopexit: + ; CHECK-NEXT: br label [[OUTER_INC]] + ; CHECK: outer.inc: + ; CHECK-NEXT: [[I_INC]] = add nuw nsw i32 [[I]], 1 +-; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i32 [[INDVARS_IV]], -1 +-; CHECK-NEXT: [[EXITCOND1:%.*]] = icmp ne i32 [[I_INC]], [[TMP0]] ++; CHECK-NEXT: [[EXITCOND1:%.*]] = icmp ne i32 [[I_INC]], [[SUB1]] + ; CHECK-NEXT: br i1 [[EXITCOND1]], label [[OUTER]], label [[EXIT_LOOPEXIT:%.*]] + ; CHECK: exit.loopexit: + ; CHECK-NEXT: br label [[EXIT]] +diff --git a/test/Transforms/IndVarSimplify/udiv.ll b/test/Transforms/IndVarSimplify/udiv.ll +index b3f2c2a6a66..3530343ef4a 100644 +--- a/test/Transforms/IndVarSimplify/udiv.ll ++++ b/test/Transforms/IndVarSimplify/udiv.ll +@@ -133,6 +133,7 @@ declare i32 @printf(i8* nocapture, ...) nounwind + ; CHECK-LABEL: @foo( + ; CHECK: for.body.preheader: + ; CHECK-NOT: udiv ++; CHECK: for.body: + + define void @foo(double* %p, i64 %n) nounwind { + entry: +-- +2.18.0 + |