[llvm-commits] [llvm] r40102 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/loadstore-alignment.ll

[Dan Gohman]

Author: djg
Date: Fri Jul 20 11:34:21 2007
New Revision: 40102

URL: http://llvm.org/viewvc/llvm-project?rev=40102&view=rev
Log:
Optimize alignment of loads and stores.

Added:
    llvm/trunk/test/Transforms/InstCombine/loadstore-alignment.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=40102&r1=40101&r2=40102&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Fri Jul 20 11:34:21 2007
@@ -8790,6 +8790,11 @@
 Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   Value *Op = LI.getOperand(0);
 
+  // Attempt to improve the alignment.
+  unsigned KnownAlign = GetKnownAlignment(Op, TD);
+  if (KnownAlign > LI.getAlignment())
+    LI.setAlignment(KnownAlign);
+
   // load (cast X) --> cast (load X) iff safe
   if (isa<CastInst>(Op))
     if (Instruction *Res = InstCombineLoadCast(*this, LI))
@@ -8985,6 +8990,11 @@
       }
   }
 
+  // Attempt to improve the alignment.
+  unsigned KnownAlign = GetKnownAlignment(Ptr, TD);
+  if (KnownAlign > SI.getAlignment())
+    SI.setAlignment(KnownAlign);
+
   // Do really simple DSE, to catch cases where there are several consequtive
   // stores to the same location, separated by a few arithmetic operations. This
   // situation often occurs with bitfield accesses.

Added: llvm/trunk/test/Transforms/InstCombine/loadstore-alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/loadstore-alignment.ll?rev=40102&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/loadstore-alignment.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/loadstore-alignment.ll Fri Jul 20 11:34:21 2007
@@ -0,0 +1,66 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {, align 16} | wc -l | grep 12
+
+ at x = external global <2 x i64>, align 16
+ at xx = external global [13 x <2 x i64>], align 16
+
+define <2 x i64> @static_hem() {
+	%t = getelementptr <2 x i64>* @x, i32 7
+	%tmp1 = load <2 x i64>* %t, align 1
+	ret <2 x i64> %tmp1
+}
+
+define <2 x i64> @hem(i32 %i) {
+	%t = getelementptr <2 x i64>* @x, i32 %i
+	%tmp1 = load <2 x i64>* %t, align 1
+	ret <2 x i64> %tmp1
+}
+
+define <2 x i64> @hem_2d(i32 %i, i32 %j) {
+	%t = getelementptr [13 x <2 x i64>]* @xx, i32 %i, i32 %j
+	%tmp1 = load <2 x i64>* %t, align 1
+	ret <2 x i64> %tmp1
+}
+
+define <2 x i64> @foo() {
+	%tmp1 = load <2 x i64>* @x, align 1
+	ret <2 x i64> %tmp1
+}
+
+define <2 x i64> @bar() {
+	%t = alloca <2 x i64>
+        call void @kip(<2 x i64>* %t);
+	%tmp1 = load <2 x i64>* %t, align 1
+	ret <2 x i64> %tmp1
+}
+
+define void @static_hem_store(<2 x i64> %y) {
+	%t = getelementptr <2 x i64>* @x, i32 7
+	store <2 x i64> %y, <2 x i64>* %t, align 1
+        ret void
+}
+
+define void @hem_store(i32 %i, <2 x i64> %y) {
+	%t = getelementptr <2 x i64>* @x, i32 %i
+	store <2 x i64> %y, <2 x i64>* %t, align 1
+        ret void
+}
+
+define void @hem_2d_store(i32 %i, i32 %j, <2 x i64> %y) {
+	%t = getelementptr [13 x <2 x i64>]* @xx, i32 %i, i32 %j
+	store <2 x i64> %y, <2 x i64>* %t, align 1
+        ret void
+}
+
+define void @foo_store(<2 x i64> %y) {
+	store <2 x i64> %y, <2 x i64>* @x, align 1
+        ret void
+}
+
+define void @bar_store(<2 x i64> %y) {
+	%t = alloca <2 x i64>
+        call void @kip(<2 x i64>* %t);
+	store <2 x i64> %y, <2 x i64>* %t, align 1
+        ret void
+}
+
+declare void @kip(<2 x i64>* %t)