[PATCH] D52263: [InstCombine] Handle vector compares in foldGEPIcmp()

[Jesper Antonsson via Phabricator via llvm-commits]

JesperAntonsson updated this revision to Diff 166117.
JesperAntonsson retitled this revision from "[InstCombine] Ignore vector compares in foldGEPIcmp()" to "[InstCombine] Handle vector compares in foldGEPIcmp()".
JesperAntonsson edited the summary of this revision.
JesperAntonsson added a comment.

Roman Lebedev commented with an elegant way to create varying integer values, so this patch makes use of that. Changed name of patch to reflect that we now handle rather than ignore vector icmps.


https://reviews.llvm.org/D52263

Files:
  lib/Transforms/InstCombine/InstCombineCompares.cpp
  test/Transforms/InstCombine/pr38984.ll


Index: test/Transforms/InstCombine/pr38984.ll
===================================================================
--- /dev/null
+++ test/Transforms/InstCombine/pr38984.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+target datalayout = "p:16:16"
+
+ at offsets = external dso_local global [4 x i16], align 1
+
+define void @PR38984() {
+; CHECK-LABEL: @PR38984(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %0 = load i16, i16* getelementptr ([4 x i16], [4 x i16]* @offsets, i16 0, i16 undef), align 1
+  %1 = insertelement <4 x i16> undef, i16 %0, i32 3
+  %2 = sub <4 x i16> zeroinitializer, %1
+  %3 = sext <4 x i16> %2 to <4 x i32>
+  %4 = getelementptr inbounds i64, i64* null, <4 x i32> %3
+  %5 = ptrtoint <4 x i64*> %4 to <4 x i32>
+  %6 = getelementptr inbounds i64, i64* null, <4 x i16> %2
+  %7 = ptrtoint <4 x i64*> %6 to <4 x i32>
+  %8 = icmp eq <4 x i32> %5, %7
+  %9 = select <4 x i1> %8, <4 x i16> zeroinitializer, <4 x i16> <i16 1, i16 1, i16 1, i16 1>
+  %10 = sext <4 x i16> %9 to <4 x i32>
+  ret void
+}
Index: lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -976,7 +976,8 @@
 
       if (NumDifferences == 0)   // SAME GEP?
         return replaceInstUsesWith(I, // No comparison is needed here.
-                             Builder.getInt1(ICmpInst::isTrueWhenEqual(Cond)));
+          Constant::getIntegerValue(I.getType(),
+                                    APInt(1, ICmpInst::isTrueWhenEqual(Cond))));
 
       else if (NumDifferences == 1 && GEPsInBounds) {
         Value *LHSV = GEPLHS->getOperand(DiffOperand);


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