[llvm] r333783 - [ConstantFold] Disallow folding vector geps into bitcasts
Karl-Johan Karlsson via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 1 12:34:35 PDT 2018
Author: karka
Date: Fri Jun 1 12:34:35 2018
New Revision: 333783
URL: http://llvm.org/viewvc/llvm-project?rev=333783&view=rev
Log:
[ConstantFold] Disallow folding vector geps into bitcasts
Summary:
Getelementptr returns a vector of pointers, instead of a single address,
when one or more of its arguments is a vector. In such case it is not
possible to simplify the expression by inserting a bitcast of operand(0)
into the destination type, as it will create a bitcast between different
sizes.
Reviewers: majnemer, mkuper, mssimpso, spatel
Reviewed By: spatel
Subscribers: lebedev.ri, llvm-commits
Differential Revision: https://reviews.llvm.org/D46379
Modified:
llvm/trunk/lib/IR/ConstantFold.cpp
llvm/trunk/test/Analysis/ConstantFolding/gep-zeroinit-vector.ll
llvm/trunk/test/Transforms/LoopVectorize/X86/constant-fold.ll
Modified: llvm/trunk/lib/IR/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=333783&r1=333782&r2=333783&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp (original)
+++ llvm/trunk/lib/IR/ConstantFold.cpp Fri Jun 1 12:34:35 2018
@@ -545,7 +545,11 @@ Constant *llvm::ConstantFoldCastInstruct
opc != Instruction::AddrSpaceCast &&
// Do not fold bitcast (gep) with inrange index, as this loses
// information.
- !cast<GEPOperator>(CE)->getInRangeIndex().hasValue()) {
+ !cast<GEPOperator>(CE)->getInRangeIndex().hasValue() &&
+ // Do not fold if the gep type is a vector, as bitcasting
+ // operand 0 of a vector gep will result in a bitcast between
+ // different sizes.
+ !CE->getType()->isVectorTy()) {
// If all of the indexes in the GEP are null values, there is no pointer
// adjustment going on. We might as well cast the source pointer.
bool isAllNull = true;
Modified: llvm/trunk/test/Analysis/ConstantFolding/gep-zeroinit-vector.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ConstantFolding/gep-zeroinit-vector.ll?rev=333783&r1=333782&r2=333783&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ConstantFolding/gep-zeroinit-vector.ll (original)
+++ llvm/trunk/test/Analysis/ConstantFolding/gep-zeroinit-vector.ll Fri Jun 1 12:34:35 2018
@@ -1,15 +1,15 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -constprop -S -o - | FileCheck %s
-; Testcase that point out faulty bitcast that cast between different sizes.
-; See "bitcast ([1 x %rec8]* @a to <2 x i16*>)" in checks below
+; Testcase that verify that we don't get a faulty bitcast that cast between
+; different sizes.
%rec8 = type { i16 }
@a = global [1 x %rec8] zeroinitializer
define <2 x i16*> @test_gep() {
; CHECK-LABEL: @test_gep(
-; CHECK-NEXT: ret <2 x i16*> bitcast ([1 x %rec8]* @a to <2 x i16*>)
+; CHECK-NEXT: ret <2 x i16*> <i16* getelementptr inbounds (%rec8, %rec8* extractelement (<2 x %rec8*> getelementptr ([1 x %rec8], [1 x %rec8]* @a, <2 x i64> zeroinitializer, <2 x i64> zeroinitializer), i32 0), i32 0, i32 0), i16* getelementptr inbounds (%rec8, %rec8* extractelement (<2 x %rec8*> getelementptr ([1 x %rec8], [1 x %rec8]* @a, <2 x i64> zeroinitializer, <2 x i64> zeroinitializer), i32 1), i32 0, i32 0)>
;
%A = getelementptr [1 x %rec8], [1 x %rec8]* @a, <2 x i16> zeroinitializer, <2 x i64> zeroinitializer
%B = bitcast <2 x %rec8*> %A to <2 x i16*>
Modified: llvm/trunk/test/Transforms/LoopVectorize/X86/constant-fold.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/X86/constant-fold.ll?rev=333783&r1=333782&r2=333783&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/X86/constant-fold.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/X86/constant-fold.ll Fri Jun 1 12:34:35 2018
@@ -1,8 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -loop-vectorize -S -mtriple=x86_64-- -o - %s | FileCheck %s
-; Testcase that point out faulty bitcast that cast between different sizes.
-; See "bitcast ([1 x %rec8]* @a to <2 x i16*>)" in checks below
+; Testcase that verify that we don't get a faulty bitcast that cast between
+; different sizes.
%rec8 = type { i16 }
@@ -28,7 +28,7 @@ define void @f1() {
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr [2 x i16*], [2 x i16*]* @b, i16 0, i64 [[TMP2]]
; CHECK-NEXT: [[TMP4:%.*]] = getelementptr i16*, i16** [[TMP3]], i32 0
; CHECK-NEXT: [[TMP5:%.*]] = bitcast i16** [[TMP4]] to <2 x i16*>*
-; CHECK-NEXT: store <2 x i16*> bitcast ([1 x %rec8]* @a to <2 x i16*>), <2 x i16*>* [[TMP5]], align 8
+; CHECK-NEXT: store <2 x i16*> <i16* getelementptr inbounds (%rec8, %rec8* extractelement (<2 x %rec8*> getelementptr ([1 x %rec8], [1 x %rec8]* @a, <2 x i16> zeroinitializer, <2 x i64> zeroinitializer), i32 0), i32 0, i32 0), i16* getelementptr inbounds (%rec8, %rec8* extractelement (<2 x %rec8*> getelementptr ([1 x %rec8], [1 x %rec8]* @a, <2 x i16> zeroinitializer, <2 x i64> zeroinitializer), i32 1), i32 0, i32 0)>, <2 x i16*>* [[TMP5]], align 8
; CHECK-NEXT: [[INDEX_NEXT]] = add i32 [[INDEX]], 2
; CHECK-NEXT: [[TMP6:%.*]] = icmp eq i32 [[INDEX_NEXT]], 2
; CHECK-NEXT: br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop !0
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