Support isampler throughout the compiler.

TRAC #23359
Signed-off-by: Jamie Madill
Signed-off-by: Shannon Woods
Author: Nicolas Capens
diff --git a/src/compiler/VariableInfo.cpp b/src/compiler/VariableInfo.cpp
index 9b0e910..e6163bd 100644
--- a/src/compiler/VariableInfo.cpp
+++ b/src/compiler/VariableInfo.cpp
@@ -99,6 +99,8 @@
       case EbtSamplerCube: return SH_SAMPLER_CUBE;
       case EbtSamplerExternalOES: return SH_SAMPLER_EXTERNAL_OES;
       case EbtSampler2DRect: return SH_SAMPLER_2D_RECT_ARB;
+      case EbtISampler2D: return SH_INT_SAMPLER_2D;
+      case EbtISamplerCube: return SH_INT_SAMPLER_CUBE;
       default: UNREACHABLE();
     }
     return SH_NONE;