[llvm] r262440 - revert r262424 because there's a *clang test* for AArch64 that checks -O3 asm output

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Tue Mar  1 19:04:09 2016
New Revision: 262440

URL: http://llvm.org/viewvc/llvm-project?rev=262440&view=rev
Log:
revert r262424 because there's a *clang test* for AArch64 that checks -O3 asm output
that is broken by this change

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
    llvm/trunk/test/Transforms/InstCombine/vec_sext.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp?rev=262440&r1=262439&r2=262440&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp Tue Mar  1 19:04:09 2016
@@ -976,28 +976,16 @@ Instruction *InstCombiner::transformSExt
     // (x <s  0) ? -1 : 0 -> ashr x, 31        -> all ones if negative
     // (x >s -1) ? -1 : 0 -> not (ashr x, 31)  -> all ones if positive
     if ((Pred == ICmpInst::ICMP_SLT && Op1C->isNullValue()) ||
-        (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue()) ||
+        (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue())) {
 
-        // The following patterns should only be present for vectors.
-        // For scalar integers, the comparison should be canonicalized to one of
-        // the above forms. We don't do that for vectors because vector ISAs may
-        // not have a full range of comparison operators. This transform,
-        // however, will simplify the IR, so we always do it.
-        //
-        // (x <=s -1) ? -1 : 0 -> ashr x, 31        -> all ones if negative
-        // (x >=s  0) ? -1 : 0 -> not (ashr x, 31)  -> all ones if positive
-        (Pred == ICmpInst::ICMP_SLE && Op1C->isAllOnesValue()) ||
-        (Pred == ICmpInst::ICMP_SGE && Op1C->isNullValue())) {
       Value *Sh = ConstantInt::get(Op0->getType(),
-                                   Op0->getType()->getScalarSizeInBits() - 1);
-      Value *In = Builder->CreateAShr(Op0, Sh, Op0->getName() + ".lobit");
+                                   Op0->getType()->getScalarSizeInBits()-1);
+      Value *In = Builder->CreateAShr(Op0, Sh, Op0->getName()+".lobit");
       if (In->getType() != CI.getType())
         In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/);
 
-      // Invert the sign bit if the comparison was checking for 'is positive'.
-      if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)
-        In = Builder->CreateNot(In, In->getName() + ".not");
-
+      if (Pred == ICmpInst::ICMP_SGT)
+        In = Builder->CreateNot(In, In->getName()+".not");
       return replaceInstUsesWith(CI, In);
     }
   }

Modified: llvm/trunk/test/Transforms/InstCombine/vec_sext.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vec_sext.ll?rev=262440&r1=262439&r2=262440&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_sext.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vec_sext.ll Tue Mar  1 19:04:09 2016
@@ -43,31 +43,3 @@ entry:
 ; CHECK:   and <4 x i32> %b.lobit.not, %sub
 ; CHECK:   or <4 x i32> %0, %1
 }
-
-;;; PR26701: https://llvm.org/bugs/show_bug.cgi?id=26701
-
-; Signed-less-than-or-equal to -1 is the same operation as above: smear the sign bit.
-
-define <2 x i32> @is_negative(<2 x i32> %a) {
-  %cmp = icmp sle <2 x i32> %a, <i32 -1, i32 -1>
-  %sext = sext <2 x i1> %cmp to <2 x i32>
-  ret <2 x i32> %sext
-
-; CHECK-LABEL: @is_negative(
-; CHECK-NEXT:  ashr <2 x i32> %a, <i32 31, i32 31>
-; CHECK-NEXT:  ret <2 x i32> 
-}
-
-; Signed-greater-than-or-equal to 0 is 'not' of the same operation as above.
-
-define <2 x i32> @is_positive(<2 x i32> %a) {
-  %cmp = icmp sge <2 x i32> %a, zeroinitializer
-  %sext = sext <2 x i1> %cmp to <2 x i32>
-  ret <2 x i32> %sext
-
-; CHECK-LABEL: @is_positive(
-; CHECK-NEXT:  [[SHIFT:%[a-zA-Z0-9.]+]] = ashr <2 x i32> %a, <i32 31, i32 31>
-; CHECK-NEXT:  xor <2 x i32> [[SHIFT]], <i32 -1, i32 -1>
-; CHECK-NEXT:  ret <2 x i32>
-}
-