[llvm-commits] [llvm] r61934 - in /llvm/trunk: lib/Analysis/ValueTracking.cpp test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll

[Chris Lattner]

Author: lattner
Date: Thu Jan  8 13:28:38 2009
New Revision: 61934

URL: http://llvm.org/viewvc/llvm-project?rev=61934&view=rev
Log:
ValueTracker can't assume that an alloca with no specified alignment 
will get its preferred alignment.  It has to be careful and cautiously assume
it will just get the ABI alignment.  This prevents instcombine from rounding
up the alignment of a load/store without adjusting the alignment of the alloca.


Added:
    llvm/trunk/test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll
Modified:
    llvm/trunk/lib/Analysis/ValueTracking.cpp

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=61934&r1=61933&r2=61934&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Thu Jan  8 13:28:38 2009
@@ -416,7 +416,7 @@
     unsigned Align = AI->getAlignment();
     if (Align == 0 && TD) {
       if (isa<AllocaInst>(AI))
-        Align = TD->getPrefTypeAlignment(AI->getType()->getElementType());
+        Align = TD->getABITypeAlignment(AI->getType()->getElementType());
       else if (isa<MallocInst>(AI)) {
         // Malloc returns maximally aligned memory.
         Align = TD->getABITypeAlignment(AI->getType()->getElementType());

Added: llvm/trunk/test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll?rev=61934&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll Thu Jan  8 13:28:38 2009
@@ -0,0 +1,26 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {, align 4} | count 4
+; rdar://6480438
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin9.6"
+	%struct.Key = type { { i32, i32 } }
+	%struct.anon = type <{ i8, [3 x i8], i32 }>
+
+define i32 @bar(i64 %key_token2) nounwind {
+entry:
+	%iospec = alloca %struct.Key		; <%struct.Key*> [#uses=3]
+	%ret = alloca i32		; <i32*> [#uses=2]
+	%"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
+	%0 = getelementptr %struct.Key* %iospec, i32 0, i32 0		; <{ i32, i32 }*> [#uses=2]
+	%1 = getelementptr { i32, i32 }* %0, i32 0, i32 0		; <i32*> [#uses=1]
+	store i32 0, i32* %1, align 4
+	%2 = getelementptr { i32, i32 }* %0, i32 0, i32 1		; <i32*> [#uses=1]
+	store i32 0, i32* %2, align 4
+	%3 = getelementptr %struct.Key* %iospec, i32 0, i32 0		; <{ i32, i32 }*> [#uses=1]
+	%4 = bitcast { i32, i32 }* %3 to i64*		; <i64*> [#uses=1]
+	store i64 %key_token2, i64* %4, align 4
+	%5 = call i32 (...)* @foo(%struct.Key* byval align 4 %iospec, i32* %ret) nounwind		; <i32> [#uses=0]
+	%6 = load i32* %ret, align 4		; <i32> [#uses=1]
+	ret i32 %6
+}
+
+declare i32 @foo(...)