[InstCombine] allow vector constants for cast+icmp fold

This is step 1 of unknown towards fixing PR28001:
https://llvm.org/bugs/show_bug.cgi?id=28001



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271810 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rotateright

lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -2439,7 +2439,7 @@ Instruction *InstCombiner::visitICmpInstWithCastAndCast(ICmpInst &ICI) {
   }
 
   // If we aren't dealing with a constant on the RHS, exit early.
-  auto *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
+  auto *CI = dyn_cast<Constant>(ICI.getOperand(1));
   if (!CI)
     return nullptr;
 

test/Transforms/InstCombine/cast.ll

@@ -214,19 +214,26 @@ define i1 @test19(i32 %X) {
   ret i1 %Z
 }
 
-; FIXME: Vector should be the same as scalar.
-
 define <2 x i1> @test19vec(<2 x i32> %X) {
 ; CHECK-LABEL: @test19vec(
-; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> %X to <2 x i64>
-; CHECK-NEXT:    [[Z:%.*]] = icmp slt <2 x i64> [[C]], <i64 12345, i64 2147483647>
+; CHECK-NEXT:    [[Z:%.*]] = icmp slt <2 x i32> %X, <i32 12345, i32 2147483647>
 ; CHECK-NEXT:    ret <2 x i1> [[Z]]
 ;
   %c = sext <2 x i32> %X to <2 x i64>
   %Z = icmp slt <2 x i64> %c, <i64 12345, i64 2147483647>
   ret <2 x i1> %Z
 }
 
+define <3 x i1> @test19vec2(<3 x i1> %X) {
+; CHECK-LABEL: @test19vec2(
+; CHECK-NEXT:    [[CMPEQ:%.*]] = icmp eq <3 x i1> %X, zeroinitializer
+; CHECK-NEXT:    ret <3 x i1> [[CMPEQ]]
+;
+  %sext = sext <3 x i1> %X to <3 x i32>
+  %cmpeq = icmp eq <3 x i32> %sext, zeroinitializer
+  ret <3 x i1> %cmpeq
+}
+
 define i1 @test20(i1 %B) {
 ; CHECK-LABEL: @test20(
 ; CHECK-NEXT:    ret i1 false

test/Transforms/InstCombine/signed-comparison.ll

@@ -13,12 +13,9 @@ define i1 @scalar_zext_slt(i16 %t4) {
   ret i1 %t6
 }
 
-; FIXME: Vector compare should work the same as scalar.
-
 define <4 x i1> @vector_zext_slt(<4 x i16> %t4) {
 ; CHECK-LABEL: @vector_zext_slt(
-; CHECK-NEXT:    [[T5:%.*]] = zext <4 x i16> %t4 to <4 x i32>
-; CHECK-NEXT:    [[T6:%.*]] = icmp ult <4 x i32> [[T5]], <i32 500, i32 0, i32 501, i32 65535>
+; CHECK-NEXT:    [[T6:%.*]] = icmp ult <4 x i16> %t4, <i16 500, i16 0, i16 501, i16 -1>
 ; CHECK-NEXT:    ret <4 x i1> [[T6]]
 ;
   %t5 = zext <4 x i16> %t4 to <4 x i32>