- %tmp = load i16* %arrayidx, align 4, !tbaa !0
- %0 = icmp eq i16 %tmp, 17791
- br i1 %0, label %land.lhs.true9, label %if.end
-
-with this patch:
-Index: InstCombine/InstCombineCompares.cpp
-===================================================================
---- InstCombine/InstCombineCompares.cpp (revision 129500)
-+++ InstCombine/InstCombineCompares.cpp (working copy)
-@@ -2506,6 +2506,18 @@
- return &I;
- }
- }
-+
-+ // Transform "icmp eq (trunc X), cst" to "icmp (and X, mask), cst"
-+ if (Op0->hasOneUse() && match(Op0, m_Trunc(m_Value(A))) &&
-+ isa<ConstantInt>(Op1)) {
-+ APInt MaskV = APInt::getLowBitsSet(A->getType()->getPrimitiveSizeInBits(),
-+ Op0->getType()->getPrimitiveSizeInBits());
-+ Value *Mask =
-+ Builder->CreateAnd(A, ConstantInt::get(A->getContext(), MaskV));
-+ return new ICmpInst(I.getPredicate(), Mask,
-+ ConstantExpr::getZExt(cast<ConstantInt>(Op1),
-+ Mask->getType()));
-+ }
- }
-
- {
+//===---------------------------------------------------------------------===//
+
+I see this sort of pattern in 176.gcc in a few places (e.g. the start of
+store_bit_field). The rem should be replaced with a multiply and subtract: